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- Trophic ecology of the gopher rockfish Sebastes carnatus inside and outside of central California marine protected areas
- Marine protected areas (MPAs) can potentially alter food web dynamics by increasing the density of fishes within their borders. Such increases in the density of potential competitors can cause generalist predators to contract the scope of their diets. This study investigated the effects of increased conspecific fish density on the diets of gopher rockfish Sebastes carnatus at a 35 yr old MPA in Point Lobos, California, and at 4 newly established MPAs in Año Nuevo, Point Lobos, Piedras Blancas, and Point Buchon in central California. Analyses were conducted for 707 stomachs collected from 2007 to 2009. Diets did not differ inside versus outside the old Point Lobos MPA in terms of prey richness, evenness, composition, or gopher rockfish trophic level. However, fish outside the MPA had greater levels of individual specialization. No consistent differences in these metrics were observed inside versus outside the 4 new MPAs, although prey composition and evenness did differ significantly among geographic locations. Diets at Año Nuevo, the most northern and shallow location, consisted predominantly of Cancer spp. and porcelain crabs (Porcellanidae), while diets from southern, deeper locations were dominated by brittle stars (Ophiuroidea). The case study of the old Point Lobos MPA indicates that fish feeding ecology may not change in an MPA after several decades. Differences in prey observed among geographic locations suggest variation in the community composition among central California's new MPAs, which may influence the effect of each MPA on food web dynamics over time. Copyright © 2015 Inter-Research., Export Date: 19 October 2015
- Loury, Bros, Starr, Ebert, Cailliet
- Deepwater habitat and fish resources associated with the Big Creek Marine Ecological Reserve,
- Big Creek Marine Ecological Reserve (BCER), located off the central California coast, has been closed to fishing since January 1994. We used side scan sonar and an occupied submersible to collect baseline information on species-habitat relationships, density, and species and size composition of fish inside and outside BCER. Forty-three dives were made in the fall of 1997 and 1998, at depths of 20-250 m. From 142 video transects, we identified over 70,000 fish from 82 taxa, including 36 species of rockfish. About 93% of the 25,159 fish inside BCER were rockfishes representing at least 20 species. Young-of-the-year rockfishes dominated rock outcrops in 20-90 m depth inside and outside BCER. Four distinct fish assemblages were associated with (1) fine, smooth sediment in deep water; (2) bedrock with uneven surface in deep water; (3) sand waves and shell hash in shallow water; and (4) boulders and organic habitats on rock in shallow water. There were no significant differences in fish density among locations (inside and outside BCER) and depths or between years. Density was significantly higher in high-relief rock habitat than in low-relief soft and mixed sediments, regardless of location. There were no consistent patterns of larger fish inside compared to outside the protected area. We recommend development of a monitoring program to continue these surveys after increased time of protection and with increased assessment effort in the appropriate habitats of economically valuable species. In addition, extending the boundaries of BCER seaward would protect habitats and fish in water depths greater than 100 m., Cited By (since 1996):18, , , Downloaded from: http://calcofi.org/publications/ccreports.html (05 June 14).
- Yoklavich, Cailliet, Starr, Lea, De Marignac, Greene, Field