Estuarine and coastal transformation is as old as civilization yet has dramatically accelerated over the past 150 to 300 years. Reconstructed time lines, causes, and consequences of change in 12 once diverse and productive estuaries and coastal seas worldwide show similar patterns: Human impacts have depleted >90% of formerly important species, destroyed >65% of seagrass and wetland habitat, degraded water quality, and accelerated species invasions. Twentieth-century conservation efforts achieved partial recovery of upper trophic levels but have so far failed to restore former ecosystem structure and function. Our results provide detailed historical baselines and quantitative targets for ecosystem-based management and marine conservation.

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Depletion, Degradation, and Recovery Potential of Estuaries and Coastal Seas

Flatfi shes are very accessible in the wild and hardy in the laboratory, thus many of the early studies of fi sh growth used fl atfi shes, especially plaice (Pleuronectes platessa) in the Atlantic and a number of species in the Pacifi c. As the science of fi sheries developed, so did the need to quantify the population structure and growth characteristics of the different fl atfi sh species. In fact, the importance of ageing fi shes and determining their growth rate was realised early in the last century (Allen 1916). Much of the early information on the aging and growth of fl atfi shes (primarily plaice) is referenced in Wimpenny (1953), Graham (1956) and Beverton & Holt (1957). Prior to the 1950s researchers had gained a fairly good understanding of the methods. A clear pattern of summer and winter growth was recognised in the otoliths, which were fi rst used in the late 1800s. Other bony structures such as opercular bones, the pectoral girdle and the concave faces of the vertebrae exhibited seasonal growth patterns (Cunningham 1905) but these were not as distinctive as those on the otoliths. The observation that a pair of rings may not delimit 1 year’s growth led to early verifi cation studies based on marginal increment analyses. Experimental work on plaice and fl ounder (Platichthys fl esus) showed that the seasonal pattern on both otoliths and scales was primarily driven by seasonal changes in water temperature rather than by variations in food availability. The use of otoliths for age estimation of fl atfi shes was not universal. Species differences slowly became apparent and methodological refi nements followed. Direct measurements of the growth of fl atfi shes were afforded by series of tagging and transplantation experiments, and laboratory or enclosure experiments (Johnstone et al. 1921). In all cases it was apparent that there was considerable variability in individual growth rates and that growth rates varied between areas. The widespread sexual dimorphism in growth with females growing faster and reaching larger sizes than males was also recognised (e.g. Johnstone et al. 1921; Bigelow & Schroeder 1953; Bagenal, 1955). The effects of gear selectivity and ontogenetic behavioural changes of fl atfi shes on the accurate estimation of age structure and growth rates were recognised, especially with the offshore movement of larger juvenile plaice from the nursery grounds and a general offshore movement with size and age. The possibility that fi shing pressure could make major changes to the age structure and growth of commercially exploited fl atfi sh populations was mentioned by Jones (1958), citing the prevalence of Rosa Lee’s phenomenon in plaice.

https://folk.uib.no/nfiag/nfiag/reprints/chapter7.pdf

Age and Growth

We utilized a long-term data base collected over a broad geographic range to examine predator size - prey size relationships for 18 species of marine fish predators from continental shelf waters off the northeast US coast. Regression analysis was used to illustrate interspecific variation in ontogenetic patterns of prey size use, gape allometries, and ratio-based trophic niche breadths. Size- based feeding strategies were assessed through comparison of frequency distributions of relative prey sizes eaten and were related to general predator feeding tactics and gape morphology. The results demonstrated that the range of prey sizes eaten expanded with increasing predator body size for each of the marine predators examined, leading to asymmetric predator size - prey size distribu- tions. Absolute maximum prey size and slopes of maximum prey size versus predator size varied widely among predator taxa. Distinct size-based feeding strategies were evident, as diets of some predators were dominated by prey that were 10 to 20% of predator size, whereas other predators frequently consumed prey >50% of predator size. Gape sizes and allometric relationships with body size were also diverse among predators and often were closely associated with maximum prey sizes. Ratio-based trophic-niche breadths generally did not expand with predator ontogeny and tended to narrow for the largest predators, which may be common for animal taxa.

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Predator size - prey size relationships of marine fish predators: interspecific variation and effects of ontogeny and body size on trophic-niche breadth

FOOD AND FEEDING HABITS BY TAXONOMIC CATEGORIES ..... 71 Carcharhinidae ........ 71 Triakidae 71 Orectolobidae ......... 71 Mobulidae 71 Dussumieridae ........ 71 Clupeidae 72 Ophichthidae ......... 72 Muraenidae ......... 72 Congridae 74 Moringuidae ......... 74 Synodontidae ......... 74 Belonidae 74 Hemiramphidae ........ 75 Bothidae 75 Holocentridae ........ 75 Syngnathidae ......... 77 Aulostoinidae ......... 77 Fistulariidae ......... 77 Atherinidae ......... 77 Mugilidae 78 Sphyraenidae ......... 78 Polynemidae ......... 78 Scombridae 78 Carangidae 79 Apogoiiidae ......... 80 Priacanthidae .... 81 Serranidae 82 Pseudochroinidae ....... 83 Pempheridae ......... 84 Lutj anidae 84 Leiognathidae 86 Sparidae 86 Mullidae 87 Cirrhitidae 88 Siganidae 88 Kyphosidae ...... ...... 89 Chaetodontidae 89 PAGE

Ecological Relationships of the Fish Fauna on Coral Reefs of the Marshall Islands

The classical approach of limnologists has been to consider the interactions between lake ecosystem components as an unidirectional flow of influence from nutrients to the phytoplankton, to the zooplankton, and finally to the fish, through successive controls by physical, chemical, and biological processes (Straskraba, 1967). The effect of planktivorous fishes on zooplankton and phytoplankton communities was not recognized until the studies of Hrbacek et al. (1961), Hrbacek (1962), Brooks & Dodson (1965) and Straskraba (1965). They showed that (1) in ponds and lakes in the presence of planktivorous fishes the zooplankton communities were composed of smaller bodied species than in those lacking planktivores, and (2) the resulting small-bodied zooplankton communities affected the phytoplankton communities. Although the variability of the phytoplankton response to fish predation showed the importance of other factors (such as nutrient limitation and interspecific competition of algae), these studies emphasized that zooplankton and phytoplankton communities can be affected by the feeding selectivity of planktivorous fishes. During the last two decades, many limnological studies have focused on this dramatic impact of fish on plankton communities. The direct response of zooplankton communities to visual fish predation (i.e. particulate feeding) has been of major interest, whereas the multilevel effects of filter-feeding fish (predation on zooplankton plus grazing on phytoplankton) have been neglected. The objectives of this review are to document fish-plankton interrelationships in order to (1) provide insights into the impact of fish on plankton communities, and (2) outline mechanistic models of planktivory according to the feeding repertory and the selectivity of the fish, the adaptive responses of the plankton, and the environmental conditions. The approach adopted here is based on field and laboratory experimental results derived from the literature on tropical and temperate freshwater (occasionally marine) systems. Four types of planktivorous fish are distinguished: the gape-limited larvae and small fish species, the particulate feeders, the pump filter feeders, and the tow-net filter feeders. For each type of planktivore, the mechanisms of prey selection are analyzed from the point of view of both the predator and the prey. To investigate the main determinants of the predator feeding selectivity, and to discuss its potential effects on prey communities, the predation-act is divided into a sequence of successive events (Holling, 1966): detection, pursuit, capture, retention, and digestion for particulate feeders; and capture, retention, and digestion for filter feeders. The strengths and weaknesses of various measures of selectivity (i.e. electivity indices), as well as their appropriate usages are considered. Available prey selection models and optimal foraging theories are analyzed for the different planktivore feeding modes. Mechanistic models based on Holling's (loc. cit.) approach are proposed for each feeding mode to determine differential prey vulnerabilities and optimal diet breadth. This review has application to several fields, including general ecology, limnology, fisheries management (for example, utilization of planktonic resources, stocking, introduction, or maintenance of natural fish populations), and biological control of the eutrophication processes (biomanipulation approaches). It emphasizes the real need for more knowledge of the feeding selectivity and food utilization of planktivores. It concludes that predator and prey are mutually adapted. Thus, in most cases, study of plankton dynamics and water quality should include the assessment of fish predation and grazing pressures.

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A review of planktivorous fishes : their evolution, feeding behaviours, selectivities, and impacts

During the summer of 1912 the Bureau of Fisheries with the cooperation of the Museum of Com;arative Zoology of Harvard Un~vers~ty, cOInInenced an oceanographic and bIOlogIcal survey of the Gulf of Maine, with special reference to its fishes to its floating plants and animals (Plankton), to the physical and chemical state of its waters and to the circulation of the latter. Cruises ;ere made on the Fisheries schooner Grampu8 during the summers and autumns of 1912, 1913, 1914, 1915 and 1916, and during the winters and springs of 1913 and 1915. The work Was interrupted by the war, but was resumed with a cruise of the Fisheries steamer Albatross in the late winter and spring of 1920, and was continued by the Fisheries steamer Halcyon during the winter and spring of 1920-21, and the summers of 1921 and 1922. The first part of the general report, dealing with the fishes was published in 1925, as Bulletin ~o (Pt. 1) of the United States Bureau of FisherIes; 1 SUbsequent parts describing the plankton of the offshore waters of the Gulf and the physical Characteristics of its waters were published in 1926-27, as Part 2. The preparation of the section on the fishes was assigned originally to W. W. Welsh, who had gathered a large body of original observations on the growth, reproduction, diet, and other phases of the lives of many of the more important species. The report was far advanced when it was interrupted by his untimely death, and H. B. Bigelow ~dertook to carry it to publication along the Imes originally laid down. The new edition, entailing a general revision and the addition of In'Uch new lnaterial, has been prepared jointly by !: B. Bigelow and by W. C. Schroeder.

William W. Welsh

Papers

Fishes of the Gulf of Maine