Showing papers in "Reviews in Fish Biology and Fisheries in 2006"

Stress-associated impacts of short-term holding on fishes

Abstract: Most sources of stress in aquaculture, fish salvage, stocking programs, and commercial and sport fisheries may be unavoidable. Collecting, handling, sorting, holding, and transporting are routine practices that can have significant effects on fish physiology and survival. Nevertheless, an understanding of the stressors affecting fish holding can lead to practices that reduce stress and its detrimental effects. The stress-related effects of short-term holding are influenced by water quality, confinement density, holding container design, and agonistic and predation-associated behaviors. Physiological demands (e.g., resulting from confinement-related stresses) exceeding a threshold level where the fish can no longer compensate may lead to debilitating effects. These effects can be manifested as suppressed immune systems; decreased growth, swimming performance, or reproductive capacity; even death. Furthermore, holding tolerance may depend upon the species, life stage, previous exposure to stress, and behavior of the held fish. Water quality is one of the most important contributors to fish health and stress level. Fish may be able to tolerate adverse water quality conditions; however, when combined with other stressors, fish may be quickly overcome by the resulting physiological challenges. Temperature, dissolved oxygen, ammonia, nitrite, nitrate, salinity, pH, carbon dioxide, alkalinity, and hardness are the most common water quality parameters affecting physiological stress. Secondly, high fish densities in holding containers are the most common problem throughout aquaculture facilities, live-fish transfers, and fish salvage operations. Furthermore, the holding container design may also compromise the survival and immune function by affecting water quality, density and confinement, and aggressive interactions. Lastly, fishes held for relatively short durations are also influenced by negative interactions, associated with intraspecific and interspecific competition, cannibalism, predation, and determining nascent hierarchies. These interactions can be lethal (i.e., predation) or may act as a vector for pathogens to enter (i.e., bites and wounds). Predation may be a significant source of mortality for fisheries practices that do not sort by size or species while holding. Stress associated with short-term holding of fishes can have negative effects on overall health and well-being. These four aspects are major factors contributing to the physiology, behavior, and survival of fishes held for a relatively short time period.

Crying wolf, crying foul, or crying shame: alien salmonids and a biodiversity crisis in the southern cool-temperate galaxioid fishes?

Abstract: The galaxioid fishes are the dominant, most speciose group of freshwater fishes (with >50 species) in the lands of the cool southern hemisphere, with representatives in western and eastern Australia, Tasmania, New Caledonia, Lord Howe Island, New Zealand, the Chatham, Auckland and Campbell Islands, Patagonian South America (Chile, Argentina), the Falkland Islands and South Africa. The group is most diverse in Australia and New Zealand. Lepidogalaxiidae is found only in Australia, Retropinnidae in Australia and New Zealand, and Galaxiidae across the entire range of the group. Many species are in serious conservation crisis for a diversity of reasons, including habitat deterioration and possibly fisheries exploitation, but there is enduring and pervasive information that shows that the group has been seriously impacted by the acclimatisation of salmonid fishes originating in the cool-temperate northern hemisphere, particularly brown and rainbow trout. With few exceptions, where these trout have been introduced there has been major decline in the galaxioids, especially Galaxiidae, as a result of a complexly interacting series of adverse impacts from these introduced fishes. In some places, centrarchids and cichlids may also have adverse impacts. In addition, there appear to have been adverse impacts from the translocation of galaxioids into communities where they do not naturally occur. In many instances it appears that displacement of the galaxioids has led to a situation where galaxioids and salmonids no longer co-occur, owing either to displacement or predation, leading to fish communities in which there is no explicit evidence for displacement. These effects are resulting in the galaxioid fishes being amongst the most seriously threatened fishes known.

Effects of exotic and translocated fish species in the inland waters of Turkey

Abstract: Throughout the world a number of problems have arisen following the introduction of new fish species; impacts of introductions are not limited to biological and ecological effects but may also have socioeconomic implications. Exotic and translocated fish species have become established in various parts of the inland waters of Turkey since the 1950s. The present paper reviewed ecological and economical effects of introduced freshwater fish of Turkey.

Fishes and salinities in the St Lucia estuarine system—a review

Abstract: The recorded salinity ranges of freshwater, estuarine and marine fish species in Lake St Lucia, a Ramsar and World Heritage Site, are documented. The freshwater group is most diverse and abundant under oligohaline conditions, although the Mozambique tilapia (Oreochromis mossambicus) was common un- der all salinity regimes. Estuary resident species also favoured oligohaline conditions but, in contrast to the freshwater taxa, were well represented in salinities up to 40 &. The marine group was most diverse and abundant within the salinity range 10-40 &, but a large number of species could also be found in salin- ities up to 70 &. Very few fish species were able to tolerate salinities between 70 & and 110 &, with only O. mossambicus surviving for extended periods in salinities above 110 &. All the aquatic macrophytes and most of the zoobenthos within the lake appear to die out within the salinity range of 50-60 &, thus creating additional stress to those fish present under such conditions. The food resources least affected by extreme hypersalinity are the microphytobenthos and detritus food chains, with detritivorous fishes being dominant when the lake is in this state. Mass mortal- ities of fishes in Lake St Lucia have been recorded under both low ( 70 &) conditions. The fish kills are often triggered by exceptionally low or high water temperatures which affect the osmoregulatory abilities of these species. Hypersaline conditions and fish mortalities under the most recent closed estuary mouth conditions (2002- 2005) are reviewed. If the surface area of St Lucia (35,000 ha) is compared to the total surface area of all South African estuaries (approximately 70,000 ha), then the possibility exists that the loss of the Lake St Lucia nursery area for estuary-associated marine fish species over the past few years may cause significant short-term declines in the future abundance of these taxa on both a local and regional scale.

Physicochemical environments and tolerances of cyprinodontoid fishes found in estuaries and salt marshes of eastern North America

Abstract: Individuals of 28 species of cyprinodontoid fishes have been reported from estuaries/salt marshes of the Atlantic and Gulf coasts of North America. Some species show limited latitudinal distributions and/or occupy a limited range of habitats; others are widely distributed and/or occupy a wide range of habitats. A literature survey was made of conditions of water temperature, dissolved-oxygen (DO) concentrations, and salinities at sites where individuals of each species had been collected, and of laboratory-determined tolerances or lethal limits and other responses to those abiotic conditions. Individuals of Cyprinodon variegatus showed the widest overall range of tolerance of environmental temperatures, −1.9–45.4°C, with Gambusia rhizophorae showing the highest lower temperature-tolerance limit, 17°C. The only species highly sensitive to hypoxia was Floridichthys carpio, which showed “stress” at DO levels of 6–8 mg kg−1. All showed use of aquatic surface respiration, except for Kryptolebias marmoratus, which uses aerial respiration in the presence of H2S, and/or under hypoxic conditions. Individuals of C. variegatus were found to tolerate ambient salinities ranging from < 0.5 to 125.2, or higher, and several species of the genus Fundulus were found to tolerate concentrations ranging from <0.5 to ≥100. However, some of the species discussed cannot tolerate salinities beyond those of dilute brackish waters. In most instances, laboratory-determined tolerance limits of temperature and salinity were wider than conditions under which individuals of these species had been found in nature. The majority of available information related to adult individuals, with few studies focused on immature stages; however, existing information permitted a brief review of spawning, incubation, and early development features in Fundulus heteroclitus. Suggestions were made, based on existing information, as to species that would be most likely to show altered population distributions resulting from continued global warming. These included five species that have tropical/subtropical, or subtropical/temperate distributions. Also, a few others were included that show extensive latitudinal distributions, most extending northward into cooler temperate regions of the Atlantic coast. At present, none of these species has shown a range alteration that can be attributed to global warming.

Standardizing fishery-dependent catch and effort data in complex fisheries with technology change

Abstract: Standardization of commercial catch and effort data is important in fisheries where standardized abundance indices based on fishery-dependent data are a fundamental input to stock assessments. The goal of the standardization is then to minimize bias due to the confounding of apparent abundance patterns with fishing power. There is a high risk of confounding between fishing power and abundance in fisheries where the fleet has altered their fishing technology over the years. Also, the spatial aspects and the fishing history can be so heterogeneous that any standardization really involves an extrapolation, for example to a hypothetical standard vessel. When the standardization involves an extrapolation, then the appropriate modeling strategy is to build a so-called estimation model, rather than a predictive model. Strategies to build such an estimation model from fishery-dependent data include: pay careful attention to subject matter, and collect information about potential confounding effects to include in the model (putting a high value on the acquisition of data on covariates); model variable catchability at a highly disaggregated scale; aim for realistic coefficients when fitting the model and pay relatively less attention to achieving precision or maximizing explained variance; adopt modern statistical methods to combine data from different sources; and if data are deficient, then apply precautionary allowances. These strategies offer some protection against bias due to confounding, in the absence of formal criteria for identifying the best model.

Video and acoustic camera techniques for studying fish under ice: a review and comparison

Abstract: Researchers attempting to study the presence, abundance, size, and behavior of fish species in northern and arctic climates during winter face many challenges, including the presence of thick ice cover, snow cover, and, sometimes, extremely low temperatures. This paper describes and compares the use of video and acoustic cameras for determining fish presence and behavior in lakes, rivers, and streams with ice cover. Methods are provided for determining fish density and size, identifying species, and measuring swimming speed and successful applications of previous surveys of fish under the ice are described. These include drilling ice holes, selecting batteries and generators, deploying pan and tilt cameras, and using paired colored lasers to determine fish size and habitat associations. We also discuss use of infrared and white light to enhance image-capturing capabilities, deployment of digital recording systems and time-lapse techniques, and the use of imaging software. Data are presented from initial surveys with video and acoustic cameras in the Sagavanirktok River Delta, Alaska, during late winter 2004. These surveys represent the first known successful application of a dual-frequency identification sonar (DIDSONTM) acoustic camera under the ice that achieved fish detection and sizing at camera ranges up to 16 m. Feasibility tests of video and acoustic cameras for determining fish size and density at various turbidity levels are also presented. Comparisons are made of the different techniques in terms of suitability for achieving various fisheries research objectives. This information is intended to assist researchers in choosing the equipment that best meets their study needs.

Vertebrate exploitation of pulsed marine prey: a review and the example of spawning herring

Abstract: Short-term bursts of prey availability occur in many ecosystems and have potential important consequences for both predator biology and ecosystem function. Examples of prey ‘pulses’ in marine ecosystems include spawning runs of several anadromous and marine fishes, horseshoe crab spawning, and salmonid juvenile outmigrations, which are exploited by numerous species of vertebrate predators. In a few cases, the fitness or demographic consequences of such predator–prey interactions are known or inferred, but too often that information remains unknown. We explored the extent of temporal and spatial variation in one example of a pulsed marine resource: the spawning of Pacific herring (Clupea pallasii). Spawning herring provide a rich, aggregated resource to which dozens of species of vertebrate predators often exhibit strong numerical responses. However, the spawning events are often variable in both time (annual differences of several to many weeks) and space (both regional and more local differences in size and timing of events). Such variability must affect more mobile predators less than area-restricted predators, and thus its effect would vary not only among species but also within species, depending on constraints of the predator life history. Unpredictability of the prey concentrations, whatever their proximate causes, may contribute to maintenance of metapopulations of prey such as herring, if unpredictability lessens the impact of predation.

Threat of non-native crayfish introductions into Turkey: global lessons.

Abstract: Introductions of crayfish species from their home range to new environments have been carried out in many parts of the world. The most important introduced crayfish species are Procambarus clarkii, Pacifastacus leniusculus, Cherax destructor, C. quadricarinatus, Orconectes limosus, O. rusticus and Astacus leptodactylus. The environmental impact of crayfish introductions can be positive, negative or neutral. However, native crayfish populations in Europe have been negatively affected by introductions of non-indigenous crayfish species from America. Negative effects of non-native crayfish introductions included displacement of native crayfish species, transfer of disease (crayfish plague), consumption of fish eggs, reduction of fish stocks, consumption of large amounts of macrophytes, indirect and direct effects on other invertebrates and upsetting production in rice fields. As a result of non-native crayfish introductions, the natural harvest and crayfish industry in Europe have been severely affected. Large quantities of Turkish A. leptodactylus were harvested (approximately 7,000 tonnes annually) and exported to Europe before the crayfish plague was observed in these populations. The total harvest of A. leptodactylus in Turkey reduced dramatically to 320 in 1991 after the plague. Therefore, although Turkey currently has no known non-native crayfish species, there is a threat of non-native crayfish introduction in order to increase crayfish productions and subsequent harvest. The North American spiny-cheek crayfish, O. limosus, has been spreading quickly down the River Danube and could soon reach neighboring countries including Turkey. The North American signal crayfish, P. leniusculus is known from Greece and could be a threat to native stocks if it is introduced into Turkey for aquaculture. Additional threats may come from the release of other North American species, which are widely available through the aquarium trade. We conclude that the spread of non-native crayfish introductions throughout Turkey will increase local problems, because introductions of non-native crayfish in many parts of the world have been known to have caused important reductions in population density and numbers of native crayfish species. Furthermore, freshwater ecosystems may be altered by such introductions and the economic viability of native crayfish species fisheries could be severely reduced in Turkey.

Fishes of Bermuda: History, Zoogeography, Annotated Checklist, and Identification keys

Abstract: islands and natural history; two topics that are, of necessity, related. Islands have been central to the development of evolutionary (think Darwin) and ecological (MacArthur and Wilson 1967) theory but it is the natural history of the species that occupy islands that is critical to advancing our understanding. These thoughts on the importance of natural history are mirrored by others (e.g. Bartholomew 1986; Dayton and Sala 2001). In this extensive text the authors bring together much of the available information on the natural history of the fishes of Bermuda. More specifically, this work provides a full treatment of the history of ichthyology on Bermuda, taxonomy, habitats, biodiversity, and conservation of the fishes. As such, it is an important reference text for students of biogeography and ichthyology. This is a comprehensive text with over 1,134 references, about 433 species in 111 families of mostly inshore ( < 200 m depth) fishes. It includes 42 watercolors, more than 3 dozen photographs, and 29 illustrations of fishes. It is unfortunate that more of the species could not have been illustrated. Of the species listed, 85 are considered new records for Bermuda and 10 are endemic including, possibly, several species of Fundulus. Despite this diversity the authors consider the fauna to be relatively depauperate (50–55% of the number of species in the Florida Keys or the Bahamas). The core of the book is the species accounts which include the nomenclature, comments on literature records, general distribution, ecology, zoogeography, commercial importance, size, and material examined. The book is further enriched with treatment of geology, inland habitats, illustrated key to families, fishery resources, and comments on conservation biology of Bermuda fishes. Appendices provide lists of Bermuda species and their occurrence in adjacent areas including the Bahamas, the U.S. coast between Cape Hatteras, North Carolina to West Palm Beach, Florida and the Florida Keys as well as location data for their personal collections. In summary, I recommend this book for biogeographers and ichthyologists especially those interested in islands and their faunas.

Past and future fisheries modeling approaches in the Philippines

Abstract: Philippines coastal fisheries research started during the colonization period in the 1800s with the basic taxonomic identification of the countries aquatic resources and a description of their distribution in national waters. Research further evolved with the change from localized fisheries governance to a centralized one, presently, with a combination of both. The dramatic postwar expansion of Philippine fisheries in the mid 1940s led to the need for sustainable resources management. In the mid-1970s, single-species fisheries approaches (i.e. specifically surplus production models) indicated the overfished state of the Philippine coastal fisheries resources. These early models together with additional ecological and socioeconomic studies, served as inputs to coastal resources management initiatives, in the context of an ecosystem approach. The implementation of further management schemes such as marine reserves and fish sanctuaries also resulted from these initiatives. The decentralization of governance of coastal resources in the 1990s led to participatory or co-management approaches for the local governance of coastal resources. The development and great improvement of ecosystem-based models in fisheries science (such as Ecopath with Ecosim [EwE]) during this period allowed for investigations into the interactions of the multispecies and multigear fisheries dynamics. Complementary models derived from single-species such as Yield per Recruit and Surplus production in conjunction with ecosystem-based (EwE-type) approaches are both needed in Philippine fisheries research. An emerging framework for sustainable Philippine fisheries management system requires mainstreaming of coastal governance with science based adaptive management for Philippine aquatic resources governance.

Elliott A. Norse and Larry B. Crowder (eds): Review of “Marine Conservation Biology: the science of maintaining the sea’s biodiversity”

Abstract: itat destruction, and loss of biodiversity, there is little question that conservation and restoration of life in the seas is necessary today. Yet important questions remain. Which species or ecosystems are the most critical? What are the restoration goals? Are there potentially negative consequences of restoration plans? Marine Conservation Biology seeks to address these questions and others by presenting the science, acknowledging the uncertainties, and considering the socioeconomic concerns that surround conservation efforts. The editors have assembled leading researchers in related fields to contribute their knowledge on marine conservation efforts. This text was reviewed by graduate students in an aquatic ecosystem conservation seminar. The editors begin with a persuasive argument for why the emerging field of marine conservation biology requires its own text. Chapter 1 presents a thorough comparison between terrestrial and marine conservation, a reoccurring theme throughout the book. Both disciplines emphasize biodiversity, focus on keystone species and vulnerable populations, and are subject to stakeholder conflicts. Marine conservation is set apart from its terrestrial counterpart by physical constraints. The inherent difficulty of observing ecosystem health beneath the water’s surface limits public awareness of existing and impending problems at sea. Chapter 2 encourages thoughtful consideration of restoration efforts, noting that we are at a loss to determine the qualities of pristine ecosystems due to the lack of historical data and a shifting baseline that comes with each new generation of marine scientists. Part One, ‘‘Marine Populations: The Basics’’ combines chapters on life history and population dynamics as they relate to conservation efforts in the sea. Chapter 3 provides a comprehensive description of various life histories for several phyla and their subsequent requirements for effective conservation. Chapter 4 is devoted to the Allee effect. While there is speculation that marine organisms may be more or less prone to Allee effects compared with terrestrial organisms, there does not appear to be enough conclusive evidence for an entire chapter devoted to this subject. We suggest a broader chapter on invertebrate population dynamics. The Allee effect is appropriately discussed in chapter 5, with an examination of the risk of extinction for marine species due to direct and indirect human impacts. The section ends with an interesting chapter on marine animal behavior analysis, used to develop highly effective fishing B. Jessen Æ J. Black Æ R. Cormier Æ A. Gabela Æ J. Murt Æ S. Pautzke Æ J. Smith Æ F. Juanes (&) Department of Natural Resources Conservation, University of Massachusetts, Amherst, MA 01003, USA e-mail: juanes@forwild.umass.edu Rev Fish Biol Fisheries (2006) 16:229–231 DOI 10.1007/s11160-006-9006-x

Review of “Fishes of the World” by Joseph S. Nelson

Abstract: book appeared. In that period, it has evolved significantly through the three previous editions to this, the fourth edition. Along the way, it has become an iconic and indispensable work in ichthyology, used extensively by laymen, consultants, ecologists, fisheries workers, students and professional ichthyologists – indeed, anyone who wants a quick, up-to-date introduction to any group of fishes and the relevant literature. The book is essentially a distillation of what we currently know or surmise about fish systematics, diversity and evolutionary history, including, as one of its major strengths – and there are many – the inclusion of fossil taxa. The contents are structured around the classification, with each taxon receiving a precis of its more important characteristics, illustrated by numerous simplified outline drawings of representatives of most of the families recognized. In scope, the book covers all the craniates, although, as is obvious from the title, the basal groups and the tetrapods receive token coverage. A complete hierarchy down to the family level (and sometimes to subfamily or even tribe) organizes the material. The numbers of genera for each level is listed, along with estimates of the number of extant species, distribution and major habitat (e.g. marine, freshwater). Sometimes, little tidbits of ecological, behavioural or other information help to enliven the text, and remind us that we are dealing with real organisms. Treatment of individual families and their constituents is, of necessity, not uniform. For example, each of the four genera of notopterids merits a couple of sentences under its own heading, but fewer than half the 112 genera of cichlids are named (I confess, however, that I prefer this treatment – it would be tedious to have to wade through the names of that number of cichlid genera). There were one or two areas where I felt additional explanations would be useful, for example, we are told that the myxinid dorsal fin is absent and the caudal fin extends onto the dorsal surface. Since the accompanying figure shows that extension reaching anteriorly for nearly one-third of the body length, one wonders why it is not called a dorsal fin (as it is in many other fishes where the two fins are continuous). And perhaps the reader should be warned that certain parts of the text do not follow the conventions of the ICZN – for example, ‘‘One species, Rhamphocottus richardsoni (Mecklenburg 2003)’’ on p. 333 does not mean that the species was described by that author in that year in a genus other than Rhamphocottus. R. Winterbottom (&) Department of Natural History, Royal Ontario Museum, 100 Queen’s Park, Toronto, Ontario M5S 2C6, Canada e-mail: rickw@rom.on.ca Rev Fish Biol Fisheries (2006) 16:227–228 DOI 10.1007/s11160-006-9004-z

On open access and optimal landings tax

Abstract: This paper develops two types of simple models on the dynamic interaction between the stock of fish and the effort expended by fishers: continuous-time/discrete-time models in which a landings tax is incorporated as a control variable available to the management authority. The continuous-time model can describe several ideal options of the optimal tax program; however, unfortunately, it is incapable of choosing the best option. Hence, using the alternative tractable discrete-time model and a computational method, the remaining task of determining a unique optimal tax program is accomplished. The fishery thus managed exhibits a regulated open access.