Species Associations and Day-night Variability of Trawl-caught Fishes from the Inshore Sponge-coral Habitat, South Atlantic Bight!
نویسنده
چکیده
Biomass, species composition, diversity, and community structure of demersal fishes were studied during the spring of 1978 in the sponge-coral habitat of the South Atlantic Bight. These results were compared with sampling at an open-shelf site. Otter trawl catch rates were an order of magnitude higher in the sponge-coral habitat than at the open-shelf site. Density and biomass estimates in the sponge-coral habitat averaged 384 individuals/ha and 31.0 kg/ha, respectively, whereas at the open-shelf site they averaged 57 individuals/ha and 3.2 kg/ha. In sponge-coral habitat samples, 101 species of demersal teleosts were taken. The Sparidae accounted for the greatest number of species (9), as well as 59% of the total number and 48% of the weight of demersal teleosts. Species diversity was highest in night-trawl tows in the sponge-coral habitat. Species associations, described by numerical classification, showed major differences in faunal assemblages between reef and open-shelf sites and between day and night samples. and offshore sites (55-183 m [30-100 fmD (Miller and Richards 1979). The most productive areas in the South Atlantic Bight, in terms of fish diversity and biomass, are the hard-bottom areas (Struhsaker 1969; Huntsman and Manooch 1978; Miller and Richards 1979; Powles and Barans 1980). The purposes of this report are to present distribution, relative abundance, and species composition of trawl-caught fishes from inshore and intermediate reefs sampled during the late spring of 1978 and to comment on the suitability of otter trawl gear for stock assessment of commercial finfish in this habitat. LIVE BOTTOM HABITAT ~ Struhsaker (1969) presented a generalized habitat classification based on substrate type and species composition in a summary of demersal fish resources off the southeastern United States (Fig. 1). The Open-shelfhabitat extends offshore from 18 m (10 fm (fathoms)) to about55 m (30 fm) and is characterized by a sandy bottom and relatively stable hydrographic conditions due to the moderating influence of the Gulf Stream (Struhsaker 1969; Mathews and Pashuk 1977). The ichthyofauna of the open shelf are relatively diverse but have a low biomass (Wenner et a1. 1979a, b, c). Abundant teleostean families are the Sparidae, Synodontidae, Serranidae, Bothidae, and Triglidae (Wenner et a1. 1979a). The sponge-coral habitat (= Struhsaker's [19691 "live bottom") is composed of isolated areas within the open-shelf habitat. These locales have a hard substrate composed of a carbonate, shell, and quartz sand conglomerate which is either exposed or covered with a thin veneer of sand to a depth of 8 cm or less (Powles and Barans 1980). This substrate provides suitable sites for the growth of dense stands of attached invertebrates (sponges, corals, echinoderms, tunicates, hydroids, and bryozoans) and algae. A recent classificati.on divides the spongeCoral habitat into estuarine and nearshore sites « 18 m [< 10 fmD, intermediate sites (18-55 m [10-30 fmD, COASTAL HABITAT I OPEN SHELF 8-IOfm I
منابع مشابه
Spatial and temporal distribution of larvae of coral reef fishes in northern Red Sea, Egypt
The larval community of coral reef fishes in the Red Sea was studied in coastal and offshore sites to determine the effects of the exposure to waves and currents and the distance from the shore in structuring the larval fish community. Plankton sampling from inshore and offshore sites and the exposed and sheltered sides of the reefs resulted in the collection of 2048 larvae representing 49 diff...
متن کاملSpecies composition in the Carangidae family during dark and light periods using the bottom trawl survey
The study aimed to estimate the effect of ecological factors such as day and night on catch species composition in fishing landings in the perisan Gulf in May 2016. In this study, were catched about 34937.18 kg marine speceis and identified of 64 groups of species and family including 56 groups of bonyfishes, 6 groups of invertabrate, 2 groups of cartilage fishes. Meanwhile, the Bushehr, Hormoz...
متن کاملSeine nets and beam trawls compared by day and night for sampling fish and crustaceans in shallow seagrass habitat
Densities of nekton were estimated by comparing catch rates of two previously uncompared gear types, a beam trawl and a seine net, by day and night in a shallow seagrass (Zostera capricorni) habitat in Moreton Bay, Queensland, Australia. A total of 39,676 fish and crustaceans representing 42 species was caught. The catch rates of nekton were 1.4–68.1 times higher at night than in the day for 8 ...
متن کاملSpatial and temporal distribution of larvae of coral reef fishes in northern Red Sea, Egypt
The larval community of coral reef fishes in the Red Sea was studied in coastal and offshore sites to determine the effects of the exposure to waves and currents and the distance from the shore in structuring the larval fish community. Plankton sampling from inshore and offshore sites and the exposed and sheltered sides of the reefs resulted in the collection of 2048 larvae representing 49 diff...
متن کاملThe Mangrove Nursery Paradigm Revisited: Otolith Stable Isotopes Support Nursery-to-Reef Movements by Indo-Pacific Fishes
Mangroves and seagrass beds have long been perceived as important nurseries for many fish species. While there is growing evidence from the Western Atlantic that mangrove habitats are intricately connected to coral reefs through ontogenetic fish migrations, there is an ongoing debate of the value of these coastal ecosystems in the Indo-Pacific. The present study used natural tags, viz. otolith ...
متن کاملذخیره در منابع من
با ذخیره ی این منبع در منابع من، دسترسی به آن را برای استفاده های بعدی آسان تر کنید
عنوان ژورنال:
دوره شماره
صفحات -
تاریخ انتشار 2009