Showing papers in "Fish and Fisheries in 2004"
TL;DR: In this paper, the authors review existing research on the social, economic and behavioural dynamics of fishing to provide insight into fisher behaviour and its implications for fisheries management, and conclude that knowledge of these dynamics is essential for effective management.
Abstract: In pursuing their livelihood, fishers develop strategies when faced with changes in regulations and other fishery conditions. Changes involve each individual in a decision‐making process governed by his/her own goals or constraints. Despite this reality, the complex dynamics of fishing has usually been ignored in designing management initiatives, which has contributed to management failures in many parts of the world. Fishers have generally been treated as fixed elements, with no consideration of individual attitudes based on their operating scales (geographical, ecological, social and economic) and personal goals. We review existing research on the social, economic and behavioural dynamics of fishing to provide insight into fisher behaviour and its implications for fisheries management. Emphasis is placed on fisher perception, and how fishers develop dynamic fishing tactics and strategies as an adaptive response to changes in resource abundance, environmental conditions and market or regulatory constraints. We conclude that knowledge of these dynamics is essential for effective management, and we discuss how such information can be collected, analysed and integrated into fisheries assessment and management. Particular emphasis is placed on small‐scale fisheries, but some examples from industrial fleets are provided to highlight similar issues in different types of fisheries.
409 citations
TL;DR: It is argued that such simple indicators have the potential to allow more stakeholders such as fishers, fish dealers, supermarket managers, consumers and politicians to participate in fisheries management and eventually hold and reverse the global pattern of convenience overfishing.
Abstract: Three simple fisheries indicators are presented: (i) percentage of mature fish in catch, with 100% as target; (ii) percent of specimens with optimum length in catch, with 100% as target; and (iii) percentage of ‘mega-spawners‘ in catch, with 0% as target, and 30–40% as representative of reasonable stock structure if no upper size limit exists. Application of these indicators to stocks of Gadus morhua, Sardinella aurita and Epinephelus aeneus demonstrate their usefulness. It is argued that such simple indicators have the potential to allow more stakeholders such as fishers, fish dealers, supermarket managers, consumers and politicians to participate in fisheries management and eventually hold and reverse the global pattern of convenience overfishing, which is defined here as deliberate overfishing sanctioned by official bodies who find it more convenient to risk eventual collapse of fish stocks than to risk social and political conflicts.
394 citations
TL;DR: It is the degree of demographic connectivity that characterizes metapopulations, with the dynamics of local populations strongly dependent upon local demographic processes, but also influenced by a nontrivial element of external replenishment, which means estimating rates of interpopulation exchange must be a research priority.
Abstract: Marine and fisheries scientists are increasingly using metapopulation concepts to better understand and model their focal systems. Consequently, they are considering what defines a metapopulation. One perspective on this question emphasizes the importance of extinction probability in local populations. This view probably stems from the focus on extinction in Levins' original metapopulation model, but places unnecessary emphasis on extinction–recolonization dynamics. Metapopulation models with more complex structure than Levins' patch-occupancy model and its variants allow a broader range of population phenomena to be examined, such as changes in population size, age structure and genetic structure. Analyses along these lines are critical in fisheries science, where presence–absence resolution is far too coarse to understand stock dynamics in a meaningful way. These more detailed investigations can, but need not, aim to assess extinction risk or deal with extinction-prone local populations. Therefore, we emphasize the coupling of spatial scales as the defining feature of metapopulations. It is the degree of demographic connectivity that characterizes metapopulations, with the dynamics of local populations strongly dependent upon local demographic processes, but also influenced by a nontrivial element of external replenishment. Therefore, estimating rates of interpopulation exchange must be a research priority. We contrast metapopulations with other spatially structured populations that differ in the degree of local closure of their component populations. We conclude with consideration of the implications of metapopulation structure for spatially explicit management, particularly the design of marine protected area networks.
371 citations
TL;DR: It is concluded that the expansion of single-species reference points to take account of the nontarget species of a fishery is tractable and desirable.
Abstract: Performance measures and reference points for the management of target species are now widely used in the fisheries of the developed world. To move us closer to an ecosystem-based fisheries management framework, we look at the prospects for expanding current single-species approaches for target species, by considering nontarget species. We also examine the development of performance measures and reference points for emergent ecosystem-level properties. We conclude that the expansion of single-species reference points to take account of the nontarget species of a fishery is tractable and desirable. In contrast, the use of performance measures for a single or a small selection of ecosystem metrics is not possible at present, owing to the absence of a clear understanding of their dynamics and a lack of underlying theory to explain their behaviour. However, recent methods that aggregate a wide range of metrics to provide an overall picture of the ecosystem status show promise and have a particular attraction because they have the potential to provide a framework for establishing a dialogue on management issues between all interested parties.
266 citations
TL;DR: A century of tagging experiments on 174 Atlantic cod (Gadus morhua) groups is reviewed and the frequency and spatial distribution of four migratory behaviors documented as discussed by the authors, confirming that migration/dispersal begets abundance.
Abstract: A century of tagging experiments on 174 Atlantic cod (Gadus morhua) groups is reviewed and the frequency and spatial distribution of four migratory behaviours documented. Of all cod groups, 41% were categorized as sedentary, 18% as accurate homers, 20% as inaccurate homers and 20% as dispersers (ranging over large areas without recognizable return migrations). All behaviours occurred over the full spatial range of cod. Coastal groups did not differ significantly from offshore (shelf) groups in the relative frequency of migratory behaviours. However, the north-east Atlantic had more sedentary and accurate homing groups than did the north-west Atlantic, which had more dispersing groups. Overall, sedentary cod groups had lower maximum historical biomass than did other groups, confirming that migration/dispersal begets abundance. Maximum historical biomass was strongly related to the area occupied [log (biomass, tonnes)] ¼ 1.58 log (range, km 2 ) + 1.529; r 2 ¼ 0.9), irrespective of migratory type (for 23 major groups a total of 22 million tonnes over 3.3 million km 2 with an average density of 7 tonnes km )2 ). Historical densities were not related to area occupied, although all large groups exhibited high densities (10–12 tonnes km )2 ; smaller groups had a wide range of density). The four migratory strategies in cod enable entrainment by diverse physical, oceanographic and biological ecosystem properties, and is key to cod success in the North Atlantic.
248 citations
TL;DR: In this article, a rule-based approach and ancillary data about distributions of fished taxa and fishing access of reporting countries are used to map global landings and to examine causal relationships between fishing and ecological change.
Abstract: Mapping global landings is an important prerequisite for examining causal relationships between fishing and ecological change. Landing statistics, typically provided with poor spatial precision, can be disaggregated into a grid system of spatial cells (30 min ·30 min) using a rule-based approach and ancillary data about distributions of fished taxa and fishing access of reporting countries. Presentation of time series catch composition is then possible for many types of marine areas including biogeochemical provinces, large marine ecosystems and exclusive economic zones.
235 citations
TL;DR: In this paper, an integrated approach evaluated how fish responded to habitat variation, and determined the consequences in terms of fish-population variability, concluding that during El Nino 1997-98, anchovy was able to exploit a small-scale temporal and spatial "loophole" inside the general unfavourable conditions.
Abstract: The Peru-Humboldt Current system (HCS) supports the world's largest pelagic fisheries. Among the world's eastern boundary current systems, it is the most exposed to high climatic stress and is directly affected by El Nino and La Nina events. In this volatile ecosystem, fish have been led to develop adaptive strategies in space and time. In this paper, we attempt to understand the mechanisms underlying such strategies, focusing on the El Nino 1997–98 in Peru from which an extensive set of hydrographic, capture and acoustic survey data are available. An integrated analysis of the data is crucial, as each has substantial shortcomings individually; for example, both catch data and acoustic surveys may easily lead to wrong conclusions. Existing hypotheses on anchovy and sardine alternations lead us to a ‘habitat-based’ synthetic hypothesis. Using our data, an integrated approach evaluated how fish responded to habitat variation, and determined the consequences in terms of fish-population variability. Various factors occurring at a range of different spatio-temporal scales were considered: interdecadal regime (warm ‘El Viejo’/cool ‘La Vieja’ decadal scale); strength and the duration of the El Nino Southern Oscillation event (interannual scale); population condition before the event (interannual scale); fishing pressure and other predation (annual scale); changes in reproductive behaviour (intra-annual scale); presence of local upwelling (local scale). During El Nino 1997–98, anchovy was able to exploit a small-scale temporal and spatial ‘loophole’ inside the general unfavourable conditions. Moreover, sardine did not do better than anchovy during this El Nino and was not able to take advantage of the ‘loophole’ opened by this short-term event. Our results question the traditional view that El Nino is bad for anchovy and good for sardine.
231 citations
TL;DR: A two-tiered approach for defining and assessing extinction risk is suggested, where simple methods requiring a few easily estimated parameters are used to triage or rapidly assess large numbers of populations and species to identify potentially vulnerable populations or species.
Abstract: The decline and disappearance of species from large parts of their former geographical range has become an important issue in fisheries ecology. There is a need to identify which species are at risk of extinction. The available approaches have been subject to considerable debate – particularly when applied to commercially exploited species. Here we have compiled methods that have been used or may be used for assessing threat status of marine organisms. We organize the methods according to the availability of data on the natural history, ecology and population biology of species. There are three general approaches to inferring or assessing extinction risk: (i) correlative approaches based on knowledge of life histories and ecology; (ii) time-series approaches that examine changes in abundance; and (iii) demographic approaches based on age- or stage-based schedules of vital rates and fisheries reference points. Many methods are well suited to species that are highly catchable and/or have relatively low productivity, but theory is less well developed for assessing extinction risk in species exhibiting narrow geographical distributions or ecological specialization. There is considerable variation in both definitions of extinction risk and the precision and defensibility of the available risk assessment methods, so we suggest a two-tiered approach for defining and assessing extinction risk. First, simple methods requiring a few easily estimated parameters are used to triage or rapidly assess large numbers of populations and species to identify potentially vulnerable populations or species. Second, the populations and species identified as vulnerable by this process can then be subject to more detailed and rigorous population analysis explicitly considering sources of error and uncertainty.
217 citations
TL;DR: More than 60 studies have been conducted using EMG telemetry that spans 18 species of free-swimming fish as discussed by the authors, and several general trends were observed in the methodology of the studies that should be adopted associated with transmitter customization, electrode placement and surgical technique.
Abstract: Electromyogram (EMG) telemetry studies that involve remotely monitoring the locomotory activity and energetics of fish are contributing important information to the conservation and management of fisheries resources. Here, we outline the development of this rapidly evolving field and formulate the studies conducted that utilize this technology. To date, more than 60 studies have been conducted using EMG telemetry that spans 18 species. Several general trends were observed in the methodology of the studies that we have highlighted as standards that should be adopted associated with transmitter customization, electrode placement and surgical technique. Although numerous studies have been methodological, there are still some deficiencies in our basic understanding of issues such as the need for individual calibration and the method of reporting or transforming data. Increasingly, this technology is being applied to address issues in conservation, management and aquaculture production. At present, the technology has been most frequently applied to the study of animal activity or energetics and to migration. Several recent studies have also focused on addressing more basic questions in ecological and evolutionary biology (e.g. parental care dynamics) similar to the large body of literature that has been collected for other taxa (e.g. marine mammals, birds), using activity telemetry. Collectively, studies conducted using EMG telemetry have contributed important information on free-swimming fish that was previously difficult to obtain. EMG telemetry is particularly effective for examining behaviour at temporal and spatial scales that are difficult using other techniques. The development of an ultrasonic transmitter based on the same proven principles as those used in the current radio transmitter technology will permit studies in other environments (i.e. marine, brackish, deep water) and on different species of fish. We encourage the continued development and refinement of devices for monitoring the activity and energetics of free-swimming fish, and also encourage researchers to consider EMG telemetry as a tool for addressing questions that are not effectively answered with other techniques.
186 citations
TL;DR: Fishing communities are often among the highest risk groups in countries with high overall rates of HIV/AIDS prevalence Vulnerability to HIV prevalence stems from complex, interacting causes that may include the mobility of many fisherfolk, the time fishermen spend away from home, their access to daily cash income in an overall context of poverty and vulnerability, their demographic profile, the ready availability of commercial sex in fishing ports and the subcultures of risk taking and hypermasculinity among some fishermen.
Abstract: Fishing communities are often among the highest-risk groups in countries with high overall rates of HIV/AIDS prevalence Vulnerability to HIV/AIDS stems from complex, interacting causes that may include the mobility of many fisherfolk, the time fishermen spend away from home, their access to daily cash income in an overall context of poverty and vulnerability, their demographic profile, the ready availability of commercial sex in fishing ports and the subcultures of risk taking and hypermasculinity among some fishermen The subordinate economic and social position of women in many fishing communities in low-income countries makes them even more vulnerable HIV/AIDS in fishing communities was first dealt with as a public health issue, and most projects were conducted by health sector agencies and NGOs, focusing on education and health care provision More recently, as the social and economic impacts of the epidemic have become evident, wider social service provision and economic support have been added In the last 3 years, many major fishery development programmes in Africa, South/South-East Asia and the AsiaPacific region have incorporated HIV/AIDS awareness in their planning The HIV/ AIDS pandemic threatens the sustainability of fisheries by eclipsing the futures of many fisherfolk The burden of illness puts additional stresses on households, preventing them from accumulating assets derived from fishing income Premature death robs fishing communities of the knowledge gained by experience and reduces incentives for longer-term and inter-generational stewardship of resources Recent projects championing local knowledge and resource-user participation in management need to take these realities into account If the fishing communities of developing countries that account for 95% of the world’s fisherfolk and supply more than half the world’s fish are adversely impacted by HIV/AIDS, then the global supply of fish, particularly to lower-income consumers, may be jeopardized
177 citations
TL;DR: It is speculated that the cues from the moon can be recognized by the higher parts of the hypothalamus–pituitary–gonadal axis, and that pituitary secretion of GtH according to the lunar cycle accounts for the lunar rhythm in gonadal development.
Abstract: Cues from the moon influence synchrony in growth, feeding, migration, behaviour and reproduction of many reef fishes. Compared with comprehensive studies on the annual and daily activities of fish, few physiological studies have paid attention to the importance of lunar cues in reproductive activities. We review mutual and interesting relationships between fish reproduction and environmental changes induced by the moon, with particular emphasis on the reproductive activity of the rabbitfishes (Siganidae). Rabbitfish species exhibit, in nature, a definitive reproductive season, which differs among the tropical areas. During the reproductive season, synchronous spawning of rabbitfish is associated with a particular lunar phase. The lunar phase used by the respective species is similar in different regions on the earth. Histological observations revealed that gonads develop synchronously towards a peak around the spawning lunar phase, after which the gonads return to spent condition. Concomitant with gonadal development, sex steroid hormones were produced under the influence of gonadotropin (GtH). Injections of human chronic gonadotropin (hCG) to the fish that are undergoing active spermatogenesis accelerated testicular maturation. These results suggest that hormonal response in maturing the gonads in rabbitfish is under the regulation of GtH, and that pituitary secretion of GtH according to the lunar cycle accounts for the lunar rhythm in gonadal development. We speculate that the cues from the moon can be recognized by the higher parts of the hypothalamus–pituitary–gonadal axis. Possible relationships between exogenous environmental factors and the lunar-reproductive rhythm are also discussed.
TL;DR: In this article, the authors investigated the dried seafood trade, centred in Chinese markets, in order to better understand the pressures its demand exerts on global marine resource stocks, using Hong Kong, the region's largest entrepot, as a focal point, in terms of product history, volume, source fisheries and species composition.
Abstract: This study investigates the dried seafood trade, centred in Chinese markets, in order to better understand the pressures its demand exerts on global marine resource stocks. Using Hong Kong, the region's largest entrepot, as a focal point, the trade in shark fins, abalone, beche-de-mer and dried fish is characterized in terms of product history, volume, source fisheries and species composition. Trends identified in the Hong Kong market are interpreted in the context of the larger Chinese market. Shark fin imports grew 6% per year between 1991 and 2000, most likely because of market expansion in Mainland China, posing increasingly greater pressures on global shark resources. In contrast, the quantities of dried abalone traded through Hong Kong remained steady, but inferences based on this trend are discouraged by suggestions of increasing preferences for fresh product forms and growing domestic production in Mainland China. Hong Kong's imports of dried beche-de-mer (sea cucumber) have decreased, while the percentage of imports re-exported has remained steady, suggesting that Hong Kong continues as an entrepot for Mainland China despite declining domestic consumption. Few conclusions can be drawn regarding dried fish products, including whole fish and fish maws, because of a lack of product differentiation in customs data, but a market survey was conducted to provide information on species composition. Comparison of Hong Kong dried seafood trade statistics to those of other key trading partners indicates that, in general, Hong Kong's duty-free status appears to encourage more accurate reporting of traded quantities. Under-reporting biases ranged from 24 to 49% for shark fin and beche-de-mer, respectively. Comparison to United Nations (UN) Food and Agriculture Organization (FAO) databases indicates additional under-reporting for shark fin such that an alternative minimum estimate of world trade is at least twice the FAO estimates in 1998–2000. The results of a survey of Hong Kong traders provide insight into their attitudes toward harvest, economic and regulatory factors, and suggest that conservation efforts are unlikely to emerge from, or be actively supported by, dried seafood trade organizations. The market's apparent sensitivity to economic sentiment, however, reveals an opportunity for consumer education to play a role in shaping future market growth and resource conservation. Recommendations are provided for improving trade statistics and for developing better analytical techniques to complement traditional methods for monitoring the exploitation and management of fisheries resources.
TL;DR: If density-dependent habitat selection is present, population growth rates in optimal habitats would be expected to be lower than in marginal habitats, and this same pattern can also evolve from a largescale, spatially autocorrelated change in a density-independent factor.
Abstract: Current methods and theory used in the study of the spatial dynamics of marine fish are problematic. Positive relationships between population abundance and occupied area are typically interpreted as evidence of density-dependent habitat selection. However, both abundance and area may co-vary with an un-parameterized variable, such as a density-independent effect. In addition, if density-dependent habitat selection is present, population growth rates in optimal habitats would be expected to be lower than in marginal habitats. This same pattern can also evolve from a largescale, spatially autocorrelated change in a density-independent factor. The theory underlying density-dependent habitat selection, the ideal free distribution, can be tautological when no a priori information of how habitat suitability changes with density is known. In this case, an ideal free distribution can be defined for any pattern of habitat-specific population growth rates. However, these problems are not insurmountable and solutions may be found by considering spatial variation in proxies of fitness and explicitly allowing for the relative importance of habitat selection (density dependent) and environmental (density independent) effects to vary with spatial scale.
TL;DR: The effect of condition on egg productivity may not be as ubiquitous or as biologically important as previously thought, and the need for greater statistical clarity in analyses of the effects of maternal condition on reproductive productivity in fishes is underscored.
Abstract: Recent research suggests that maternal condition positively influences the number of eggs spawned in fishes. These studies commonly choose a priori to use body length rather than weight as an explanatory variable of offspring production, even though weight is usually the better predictor of fecundity. We are concerned that consistent exclusion of body weight as a predictor of egg production inflates the variance in fecundity attributable to maternal condition. By analysing data on three populations of Atlantic cod (Gadus morhua, Gadidae) and 10 populations of brook trout (Salvelinus fontinalis, Salmonidae), we illustrate the need for a statistically defensible method of model selection to distinguish the effects of maternal condition on egg production from the effects of body size alone. Forward stepwise regression and null model analyses reveal how length-based regressions can significantly over-estimate correlations between condition and fecundity, leading us to conclude that the effect of condition on egg productivity may not be as ubiquitous or as biologically important as previously thought. Our work underscores the need for greater statistical clarity in analyses of the effects of maternal condition on reproductive productivity in fishes.
TL;DR: This paper reviews and critique recent publications that report equivocal conclusions favouring the absence or presence of consciousness in various fishes, and demonstrates that there are alternative perspectives which support the existence of conscience in fishes as a plausible concept.
Abstract: There is growing societal and scientific interest in the welfare status of fish used for commercial enterprise. As animal welfare is primarily concerned with the quality of life of a conscious, sentient organism, the question of whether fishes are even capable of consciousness must first be addressed in order to assess their welfare status. Recently, there has been a resurgence of research investigating the biological basis for human consciousness, and our current understanding of the cognitive mechanisms underlying fish behaviour has likewise improved significantly. Combined, these research perspectives create an opportunity to better comprehend the phylogeny of traits associated with consciousness, as well as the emergence of consciousness itself during vertebrate evolution. Despite the availability of this literature, contemporary reviews or published studies investigating the probability of conscious states occurring in fishes often do so without considering new perspectives or data. In this paper, we review and critique recent publications that report equivocal conclusions favouring the absence or presence of consciousness in various fishes. By introducing other data into these analyses, we demonstrate that there are alternative perspectives which support the existence of consciousness in fishes as a plausible concept. An accurate assessment of the mental capacity of fishes will require enhanced knowledge of their forebrain neuroanatomy, an understanding of how such structures mediate behavioural responses, and an analysis of that information within the context of contemporary theory related to the evolution of consciousness in higher vertebrates.
TL;DR: This critical review argues that several methods for the estimation and prediction of numbers-at-age, fishing mortality coefficients F, and recruitment for a stock of fish are too hard to explain to customers and do not pay enough attention to weaknesses in the supporting data, assumptions and theory.
Abstract: This critical review argues that several methods for the estimation and prediction of numbers-at-age, fishing mortality coefficients F, and recruitment for a stock of fish are too hard to explain to customers (the fishing industry, managers, etc.) and do not pay enough attention to weaknesses in the supporting data, assumptions and theory. The review is linked to North Sea demersal stocks. First, weaknesses in the various types of data used in North Sea assessments are summarized, i.e. total landings, discards, commercial and research vessel abundance indices, age-length keys and natural mortality (M). A list of features that an ideal assessment should have is put forward as a basis for comparing different methods. The importance of independence and weighting when combining different types of data in an assessment is stressed. Assessment methods considered are Virtual Population Analysis, ad hoc tuning, extended survivors analysis (XSA), year-class curves, catch-at-age modelling, and state-space models fitted by Kalman filter or Bayesian methods. Year-class curves (not to be confused with ‘catch-curves’) are the favoured method because of their applicability to data sets separately, their visual appeal, simple statistical basis, minimal assumptions, the availability of confidence limits, and the ease with which estimates can be combined from different data sets after separate analyses. They do not estimate absolute stock numbers or F but neither do other methods unless M is accurately known, as is seldom true.
TL;DR: Examination of the ranges of some amphidromous species, and of the distributions of genera to which amphodromous fishes belong, strongly suggests that amphidromy, especially in the gobies of the subfamily Sicydiinae, is a widespread, probably ancestral trait.
Abstract: Amphidromy is a frequent attribute of fish faunas of remote islands, where the presence of freshwater fishes creates perplexity as to how such remote places came to have ‘freshwater fish’. Not infrequently, the fact that amphidromous species spend part of their lives in the sea is invoked as indicating that such species have marine ancestries, and this is the implied explanation for presence of freshwater fishes on islands. However, examination of the ranges of some amphidromous species, and of the distributions of genera to which amphidromous fishes belong, strongly suggests that amphidromy, especially in the gobies of the subfamily Sicydiinae, is a widespread, probably ancestral trait. Rather than such amphidromous fish having a marine ancestry, their marine life stages are themselves the likely key element in explaining their distributions.
TL;DR: Ghoti as mentioned in this paper proposed an intergenerational costbenefit analysis (CBA) which takes into account the fact that current restoration efforts may produce benefits, in particular, fish protein, to future generations, and that these benefits need to be valued using the respective discounting clocks of the generation receiving them.
Abstract: Ghoti papers Ghoti aims to serve as a forum for stimulating and pertinent ideas. Ghoti publishes succinct commentary and opinion that addresses important areas in fish and fisheries science. Ghoti contributions will be innovative and have a perspective that may lead to fresh and productive insight of concepts, issues and research agendas. All Ghoti contributions will be selected by the editors and peer reviewed.
Etymology of Ghoti George Bernard Shaw (1856-1950), polymath, playwright, Nobel prize winner, and the most prolific letter writer in history, was an advocate of English spelling reform. He was reportedly fond of pointing out its absurdities by proving that ‘fish’ could be spelt ‘ghoti’. That is: ‘gh’ as in ‘rough’, ‘o’ as in ‘women’ and ‘ti’ as in palatial.
Abstract
Conventional cost–benefit analysis (CBA) tends to show that most ecosystem restoration programmes are not worthwhile in economic terms. This is because discounting puts more weight on current net benefits than future ones. I suggest that this is partly because conventional CBA is based on the current generation's time perspective (termed here the ‘discounting clock’). That is, net benefits are discounted starting when the analysis is carried out (the present). To tackle this problem, I propose the use of an intergenerational CBA, which takes into account the fact that current restoration efforts may produce benefits, in particular, fish protein, to future generations, and that these benefits need to be valued using the respective discounting clocks of the generation receiving them. This approach appears to meet the requirements imposed by most management jurisdictions, where there is an explicit or implied requirement to account for benefits to future generations in decision-making concerning the use and management of marine resources.
TL;DR: All well sampled phylogenies for this group fit a pattern reflecting Gondwanan break-up, and Grounds for strictly dispersalist hypotheses are not well founded for any cichlid disjunct distribution, leaving vicariance alternatives as the only explanation.
Abstract: Phylogenetic analyses dealing with disjunct distributions (distributions that require marine dispersal or vicariant events) are reviewed for the Cichlidae. The most corroborated relationship between clades across a Gondwanan disjunction is the sister relationship between Indian and Malagasy cichlids. The minimum age of the Cichlidae as implied by the fossil record is at odds with the timing of the Cretaceous break of the Indian–Madagascar landmass. All well sampled phylogenies for this group fit a pattern reflecting Gondwanan break-up. Grounds for strictly dispersalist hypotheses are not well founded for any cichlid disjunct distribution, leaving vicariance alternatives as the only explanation.
TL;DR: This Rockfish Symposium brought together rockfish biologists and fisheries managers from California to British Columbia, along with representatives from Indian tribes in Wash-ington State to discuss the steep declines of these magnificent fishes.
Abstract: Rockfish, among the most common benthic fish on the Pacific coast of North America, are members of the highly diverse genus Sebastes (Scorpaenidae). About 100 described species are found in the North Pacific from Japan to the Gulf of California, with a few species in the South Pacific and the Atlantic (Love et al. 2002). Rockfish diversity is highest in California, where 54 species co-occur off Santa Barbara; 35 species are found in Washington State, 26 of which are in inland marine waters; 36 species are recorded in British Columbia (coastal and inland marine waters combined) 1. At present, 12 species occur commonly in the inland marine waters of Puget Sound in Washington State, but the reported catch consists almost entirely of just two species, the quillback (Sebastes maliger) and the copper rockfish (S. caurinus) 1. High fishing pressures from the 1960s to the 1990s all along the Pacific coast have driven rockfish populations so low that recovery now seems to be problematic. To discuss these issues, this Rockfish Symposium brought together rockfish biologists and fisheries managers from California to British Columbia, along with representatives from Indian tribes in Wash-ington State. The keynote speaker, Milton Love Santa Barbara), shared nearly 50 years of his research on Pacific rockfish, declaring that 'since the age of nine, rockfish were all I really cared about'. Love is an avid fisherman who eventually became a biologist, and recently co-authored a monograph on NE Pacific rockfishes (Love et al. 2002). In 1990, he co-authored a pioneering paper on life-history characteristics of 19 species of rockfish, by dissecting fish at a seafood processing plant (Love et al. 1990). With extensive underwater experience, Love reported that in southern Califor-nia you can still see 20–25 species of rockfish on a dive – 'they dominate every habitat, [but] there are very, very few adult rockfish left of all species … they're almost all small'. Overfishing is blamed for the steep declines of these magnificent fishes. Love catalogued the gradual improvements in fishing technology and consequent moves into increasingly deep waters by fishers over the last 100 years. Even by the early 1960s, the Californian catch was dominated by single healthy year classes, large old animals having already been depleted. In contrast, Love described one reef near a deep canyon wall, that does not show up on sonar and that is still populated with enormous rockfish. Other talks included information …