Location, Location, Location: Incorporating Spatial Context into Fisheries Research

Fisheries biologists often ignore the spatial context of their field samples even though considering the landscape has increased understanding of organism-habitat relationships in other systems. The goal of our study is to test if the spatial context of habitat-specific sampling influenced age-0 largemouth bass distribution and diet in a Great Plains reservoir. We used standardized 100 m samples collected from 36 patches representing five habitat types (vegetation, beach, rock, open water, wood) to assess the spatial patterns of age-0 largemouth bass distribution and diets. Age-0 largemouth bass were most abundant in vegetated and beach habitats (mean CPUE LMB/m²; vegetation: 0.011, beach 0.013, rock: 0.004, open water: 0.000, wood: 0.000, ANOVA p=0.007). Diet composition was similar in vegetated and beach habitats; but more fish were eaten in the rarely used, but highly profitable, rock habitat. Spatial context influenced diet composition as age-0 largemouth bass ate more benthic invertebrates in the riverine zone and less terrestrial invertebrates in the transitional zone. Age-0 largemouth bass ate more benthic invertebrates inside rather than outside of embayments (mean prey weight/LMB; inside 0.017, outside 0.004; t-test p=0.012). In summary, interpreting fisheries samples in a spatial context can explain additional variation in young sportfish distribution.