Recruitment

Recruitment of Estuarine Fishes: Longterm Research and Monitoring

This program is designed to answer the following questions: What is the timing of larval recruitment to temperate estuaries? Has this changed with the climate? How does this vary between resident and transient species? What, if any, is the relationship between larval recruitment and settlement? Is there a relationship between larval supply (abundance) and juvenile settlement/abundance?

In an attempt to answer some of these questions, we have collected weekly, quantitative ichthyoplankton samples over 26 years (1989-2015) to identify temporal scales of variability in the abundance and occurrence of larval fish assemblages inside Little Egg inlet (see map). We collected species that spawn in the estuary, both the estuary and the continental shelf, continental shelf, and the Sargasso Sea. Analyses suggest an annually repeated seasonal progression of species assemblages.

In recent years the emphasis on fish recruitment has focused more on survival of postsettlement young-of-the-year (YOY). In an effort to evaluate the effectiveness of this approach we have attempted to determine the relationship between larval abundance for resident and transient fishes (18 species) based on the above ichthyoplankton sampling program inside Little Egg Harbor, and subsequent abundance in sampling gears (traps, trawls) designed to capture young-of-the-year (YOY) fishes.

In another attempt to determine annual variation in fish habitat utilization we conducted a large-scale perspective of fish assemblage structure across an ocean-estuarine ecotone based on sampling at stations along 40 km from the Mullica River (river), Great Bay (bay), and the adjacent inner continental shelf (ocean) in southern New Jersey. These observations, to date, indicate that large-scale patterns in the structure of this estuarine fish assemblage are primarily a result of individual species’ responses to dominate environmental gradients, as well as ontogenetic migrations, whereas smaller-scale patterns appear to be the result of habitat associations that are most likely driven by foraging, competition, and or predator avoidance strategies.

Specific Research Projects

Utilizing data from the past 25+ years, time during which this project has been active, we have contributed to the Southeast Area Monitoring Program (SEAMAP). SEAMAP facilitates collection, management, and dissemination of fishery-independent data collected in southeastern U.S. waters.

Visit the Ongoing Research page to see our latest work on estuarine fish recruitment.