Authors

Brandyn Lucca

Type

Text

Type

Thesis

Advisor

Warren, Joseph D

Date

2017-05-01

Keywords

Abundance, Active acoustics, Atlantic menhaden, Biomass, Long Island, Target strength | Biological oceanography -- Acoustics

Department

Department of Marine and Atmospheric Science

Language

en_US

Source

This work is sponsored by the Stony Brook University Graduate School in compliance with the requirements for completion of degree.

Identifier

http://hdl.handle.net/11401/77758

Publisher

The Graduate School, Stony Brook University: Stony Brook, NY.

Format

application/pdf

Abstract

Forage fish are an ecological cornerstone that trophically link primary production with pelagic predators such as piscivorous fish, marine mammals, seabirds, and humans. Atlantic menhaden (Brevoortia tyrannus) are one such forage fish species that can be found in both estuarine and coastal waters from the Gulf of Maine to Florida throughout the year. Alongside their ecological importance as prey for commercially important species such as striped bass and bluefin tuna, menhaden are fished to be used as bait or reduced into oil. New York has an especially rich history with the commercial harvesting of menhaden beginning in the late 17th century. Despite their relative ecological and economic importance, there is a paucity of quantitative data that describes the spatial and temporal distributions of menhaden in many regions throughout their geographic range. A promising method to study the distribution of menhaden is active acoustics which has been utilized in other fisheries to provide relatively time-efficient quantitative data with broad spatial coverage and high resolution. Acoustic surveys were conducted in two different habitats (estuarine, coastal) where menhaden are found during the 2014 and 2015. Menhaden aggregations were very patchy and there was evidence of significant clustering in both habitats. Coastal menhaden abundance and biomass were relatively constant throughout the summer with a peak in the late-summer. Conversely, estuarine menhaden abundance and biomass biomass peaked in late-spring and early-fall, and decreased by three orders of magnitude by mid-fall. Mean target strength (TS) of coastal menhaden was relatively constant which suggested no differences in the size classes of fish. Conversely estuarine TS distributions shifted throughout the sampling effort which were consistent with changes in the size classes of fish as they grow and migrate in and out of the estuarine habitat. This study demonstrates that active acoustics is a viable tool for measuring menhaden abundance and biomass in both coastal and shallow-water (< 4 m) estuarine waters. | 43 pages

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