English (United Kingdom)

https://curated-unify.zendy.io/wp-json/zendy-region/v1/featured_content/oa?rat=en

https://curated-unify.zendy.io/wp-json/zendy-region/v1/highlighted_journal/

Global: Zendy Plus annual

Presents the access of premium content as premium feature

Premium Content

Presents the keyphrase highlighting as premium feature

Keyphrase Highlighting

Presents the summarisation as premium feature

Summarisation

Insights

Presents the pdf analysis as premium feature

PDF Analysis

Presents the zaia usage as premium feature

ZAIA

Global: Zendy Tools annual

Global: Zendy Free Plan

Global: Zendy Tools monthly

Global: Zendy Plus monthly

Dietary analyses of Intestinal contents from 96 bluellne tlleflsh Caulolatilus microps (mean TL = 528 ± 94 mm SO) and 32 snowy grouper Epinephelus nlveatus (mean TL = 609 ± 146mm SD) collected from the shelf environments (123·256 m) in the lower Florida Keys during July 1980 and May-October 1981, revealed that the two predatory species ex· hlbited different feeding strategies. Bluellne tlleflsh preyed principally on benthic In· vertebrates, and snowy grouper on fish. Copepods, ophluroids, and gastropods comprised 60% of the numerical, and urochordates 40% of the volumetric intestinal contents of bluellne tilefish. Frequency of occurrence of prey consumed by tlleflsh exceeded 50% only for two major taxa Polychaeta and Natantla. Osteichthyes comprised 47% and 52% of the numerical and volumetric consumption of prey, respectively, by snowy grouper, and occurred in 72% of the Intestines; cephalopods ranked second in numerical importance (18%), and brachyuran crabs second in volumetric Importance (29%). Differences in prey taxa, space niche, and fish anatomy Indicated that bluellne tilefish and snowy grouper occupy different trophic niches, which reduc·e.~ Interspecific competition. Two species of continental shelf fishes, the blueline tilefish, Cau/olatilus microps Goode and Bean 1878, and the snowy grouper, Epinephelus niveatus (Valenciennes, 1828), are commercially exploited in the West-Central Atlantic and in the Gulf of Mexico, primarily off Florida. These species are harvested from the same biotopes, using the same gear and the same bait; however, little is known of their life history parameters, such as respective trophic niches. The blueline tilefish has been described as an epibenthic browser (Dooley, 1978), and its diet includes polychaetes, mollusks, sipunculids, crustaceans, echinoderms, ascideans, and fish (Ross, 1982). Snowy grouper are presumed to feed near the bottom on fishes, crustaceans, and squid. 'Current address: Bureau of Marine Research, Florida Department of Natural Resources, 100 Eighth Avenue S.E., St. Petersburg, FL 33701-5095. 77 Investigational hypotheses were that blueline tilefish and snowy grouper, as predators, have evolved generalized feeding strategies to cope with the continental shelf environment, and that some degree of niche specialization exists to facilitate coexistence between the two species (Bielsa, 1982). Specific objectives of this study were to determine the dietary components of the blueline tilefish and snowy grouper, and to elucidate possible trophic interactions between the predatory fish species. MATERIALS AND METHODS Fish were collected from Atlantic offshore waters along the lower Florida Keys, between 24°16'-24°26' N. Latitude and 81 °43'-82°0'W. Longitude. Samples were from the commercial catch, taken by hook-and-line at water depths between 123-256 m. Squid was the principal bait. Fish were collected in July 1980, 1 Bielsa and Labisky: Food Habits of Blueline Tilefish, Caulolatilus microps, and Snowy Published by The Aquila Digital Community, 1987 78 Bielsa, L.M. and R.F. Labisky and in May, June, July, and October 1981. All fish were measured for total length (mm TL). Both fish species, when raised to the surface from deep waters, everted their stomachs because of the decompression of the gas bladder. Consequently, only intestinal contents were available for analysis, which could have biased the results in favor of food items that were resistant to digestion. Intestines were removed, labeled, and stored in 10% buffered formalin. Food items were later removed from the intestines, washed in water, and preserved in 50% isopropyl alcohol. Intestinal contents were separated to the lowest identifiable taxon. Identification was facilitated by texts and keys (Rathbun, 1898, 1925; Benedict, 1900; Williams, 1965; Manning, 1969; Pequegnat, 1970; Felder, 1973; Abbott, 1974; Nelson, 1976; Warner, 1977; Barnes, 1980). Each taxon was quantified by number, volume (water displacement), and frequency of occurrence of food items. The numerical proportion of each food category also was calculated for fish size-class:~ 500 mm, 501-600 mm, 601-700 mm, and~ 701 mm TL for tilefish; and ~ 510 mm, 511-685 mm, and ~ 686 mm TL for grouper. The relative importance of each food category was determined by computing the index of relative importance (IRI = (N + V) F), where N = numerical percentage, V = volumetric percentage; F = frequency of occurrence percentage (Pinkas et a/., 1971). The presence or absence of biogenic sediment also was recorded for each intestine.

Food Habits of Blueline Tilefish, Caulolatilus microps, and Snowy Grouper, Epinephelus niveatus, from the Lower Florida Keys