Proposed Abstract Title

Habitat use and diet of juvenile surf smelt and Pacific sand lance in Puget Sound, Washington

Type of Presentation

Poster

Session Title

Forage Fish Management and Conservation in the Salish Sea

Location

2016SSEC

Description

Forage fish, such as Pacific sand lance (Ammodytes hexapterus) and surf smelt (Hypomesus pretiosus) are important components of the marine food web where they serve as prey for birds, other fish, and marine mammals. However, factors such as habitat use patterns and feeding ecology for many forage fish species are poorly understood. Considering that nearshore eelgrass habitats in Puget Sound are used as nursery and rearing grounds by other fish species, we used beach seine hauls to investigated the use of nearshore eelgrass beds by the juvenile life stages of these fish relative to areas lacking vegetative substrates. We also investigated fish catches in open shorelines vs. embayments. Our study objectives were to measure fish abundance within each of the habitat types and identify important food items for both of these forage fish species. We completed 330 beach seine hauls at 11 study sites in central Puget Sound during late spring-early summer. Sampling was stratified to include daytime and nighttime conditions, and we captured more than 2,500 surf smelt and 59,000 sand lance. Although total catch was dominated by sand lance, these fish were captured infrequently but in very high numbers. For surf smelt, the highest percentages of fish were captured in embayments with bare substrates (38%), and the lowest percentages were captured in embayments with eelgrass (14%). Nearly all (>99%) of the sand lance were captured in bare habitats and a slightly higher percentage of fish were captured in embayments (56%) compared to open shorelines (43%). Diet analysis revealed that surf smelt had a preference for cyclopoid copepods and cladocerans, which plankton surveys showed were not a highly available food item in our study area. Sand lance were more opportunistic feeders as evidenced by presence of the relatively abundant calanoid copepods in their diet.

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Habitat use and diet of juvenile surf smelt and Pacific sand lance in Puget Sound, Washington

2016SSEC

Forage fish, such as Pacific sand lance (Ammodytes hexapterus) and surf smelt (Hypomesus pretiosus) are important components of the marine food web where they serve as prey for birds, other fish, and marine mammals. However, factors such as habitat use patterns and feeding ecology for many forage fish species are poorly understood. Considering that nearshore eelgrass habitats in Puget Sound are used as nursery and rearing grounds by other fish species, we used beach seine hauls to investigated the use of nearshore eelgrass beds by the juvenile life stages of these fish relative to areas lacking vegetative substrates. We also investigated fish catches in open shorelines vs. embayments. Our study objectives were to measure fish abundance within each of the habitat types and identify important food items for both of these forage fish species. We completed 330 beach seine hauls at 11 study sites in central Puget Sound during late spring-early summer. Sampling was stratified to include daytime and nighttime conditions, and we captured more than 2,500 surf smelt and 59,000 sand lance. Although total catch was dominated by sand lance, these fish were captured infrequently but in very high numbers. For surf smelt, the highest percentages of fish were captured in embayments with bare substrates (38%), and the lowest percentages were captured in embayments with eelgrass (14%). Nearly all (>99%) of the sand lance were captured in bare habitats and a slightly higher percentage of fish were captured in embayments (56%) compared to open shorelines (43%). Diet analysis revealed that surf smelt had a preference for cyclopoid copepods and cladocerans, which plankton surveys showed were not a highly available food item in our study area. Sand lance were more opportunistic feeders as evidenced by presence of the relatively abundant calanoid copepods in their diet.