An Analysis of the Variability of Fish Populations Taken by Otter Trawl in Biscayne Bay, Florida

Abstract

Three bottom habitats in Biscayne Bay were sampled by 120 trawl samples taken during both day and night from April to August 1963. Daylight samples contained 1,391 fishes representing 41 species. Night samples contained 1,440 fishes and 49 species. The number of species per sample followed a Poisson distribution, the number of individuals per sample followed a negative binomial distribution, and the number of individuals per species followed Fisherˈs logarithmic series. The following generalizations apply to both number of species and number of individuals. More fishes were taken in the Thalassia area than in the Thalassia‐sand area, which in turn had more than the mud‐sand area. More were taken at night than during the day. Tidal direction had no significant effect. Analysis of data on the sample variance for paired 2‐minute samples showed that seven to eight replicates are needed to detect a difference of five species and 10 samples are needed to detect a 10% change in the number of individuals with 95% confidence.

Trophic Relationships in a Seagrass Community (Thalassia testudinum), in Card Sound, Florida. Fish Diets in Relation to Macrobenthic and Cryptic Faunal Abundance

“…The highest value in one sample was 0.47 g dry/m a found in June 1973. Roessler (1965). The wet weight of fish per unit area varies from a daytime high of 15 g/m a in September 1972, to a nighttime low of 0.6 g/m a in March 1973 (Table 3) However, the analysis of gut contents is qualitative and the percentages in Table 4 refer to the relative number of fish of each species examined which were empty or which contained identifiable remains from each prey taxon.…”

Caloosahatchee Estuary conceptual ecological model

“…Fish densities are typically greater in grass bed habitat within South Florida's estuaries and coastal lagoons than in adjacent habitats (Reid 1954, Tabb et al 1962, Roessler 1965, Yokel 1975, Weinstein et al 1977. Grass beds provide cover and protection from predation for animals living in them (Zieman 1982, Heck et al 1997.…”

A Restored Seagrass (Thalassia) Bed and Its Animal Community

“…In an early study of Biscayne Bay, Roessler (1965) found that samples collected at night had significantly greater numbers* of fishes than had those collected in •A referee points out that species identity can be most important.-Ed. daytime; however, in the studies made at Turkey Point, comparisons of day and night catches showed no significant differences (Roessler & Tabb, 1974).…”