Understanding The Long-Term Dynamics Of Non-Traditional Species In Bentho-Demersal Communities

No abstracts are to be cited without prior reference to the author.

The demersal component of many fish communities usually consists of high profile and commercially valuable species that are targets of fisheries, plus a diverse group of lesser known species that have minimal commercial value and focus. Yet ecologically these traditionally nontargeted species are often a major biomass sink in marine ecosystems and can also be critical in the functioning of bentho-demersal food webs. I examined the biomass trajectories of several species of skates, cottids, lophiids, anarhichadids, zooarcids and similar species in the U.S. northwest Atlantic ecosystem to determine if their relative abundance has changed across the past four decades. Distribution and stomach contents of these species were also evaluated over time to further evaluate the relative importance of these species. Of particular emphasis was testing the hypothesis of a possible competitive release from gadids and pleuronectiformes, groups which have both experienced a high degree of population decline due to overfishing during this period. I also explored the hypothesis that despite a large amount of bottom disturbance from mobile fishing gear, the benthos and forage fish communities provided a consistent amount of food to maintain and expand populations of these non-traditional species. Results indicate that some of these fish species are the dominant piscivores, benthivores, and scavengers in this ecosystem, and in general have either maintained a rather consistent population size or have increased in abundance (and expanded in distribution) over the past several decades. Non-traditional fish species are an often overlooked but important component of bentho-demersal fish communities.