# A Geospatial Approach to Improving Fish Species Detection in Maumee Bay, Lake Erie
## 4 Discussion  
Incorporation of a hot spot analysis and subsequent hybrid sampling was beneficial to the EDM program in Maumee Bay in 2017 but success varied by gear. The resulting hot spots were a better predictor of species-rich areas for the shallow water gears, electrofishing and paired fyke nets, compared to bottom trawling. Random site selection by depth strata for shallow waters may often select sites away from the shore in sand or mudflat areas that  
Figure 2: Species accumulation curves for sampling gears at Maumee Bay in 2017. The triangle symbol indicates the species accumulation curve for traditional sampling sites (\(n=15\)), while the circle symbol indicates the species accumulation curve for combined hot spot (\(n=5\)) and selected traditional (\(n=10\)) sampling sites. The solid lines represent the interpolated data while the dashed lines represent the extrapolated data. The shaded areas show 95% confidence intervals for each line. lack structure and are ecological deserts, leading to lower catch and species diversity. Many species use nearshore habitat as cover for protection from predators, for feeding, or traverse along shorelines as they move to new locations [25]. Past samples that collected diverse catches identified by the hot spot analysis may have been associated with vegetative cover or other areas where fish can take refuge (e.g., woody debris). Unfortunately, the EDM program did not consistently record substrate, vegetation, or woody debris during these survey years, so we are unable to validate this hypothesis. However, the use of this analysis to identify species-rich areas may be a proxy for locating preferred fish habitats. Bottom trawl sampling efficiency likely was not improved by incorporating this analysis because trawl locations were in waters greater than 2 m, where heavy vegetation is less likely due to the turbidity of the area and could not be conducted over structured areas such as rocks and woody debris due to risk of net hang ups. Additionally, many of the 2017 traditional bottom trawl sites were coincidentally located in hot spot areas (7 out of 15) and may have contributed to the similar species accumulation and sampling efficiency of traditional sampling compared to hybrid sampling. Including targeted sampling effort in shallow water locations designated as \"hot spots\" improved species accumulation (detected species at a faster rate) and sampling efficiency (detected a higher proportion of estimated total species present) for boat electrofishing and paired fyke nets. The difference in the number of sites required to reach 95% species detection was estimated to be considerably lower when including targeted sampling for electrofishing and paired fyke netting as well. However, species accumulation and sampling efficiency were not improved at deeper sites using bottom trawling. Despite three times as much effort being allocated to traditional sites, several species were collected at hot spot sites in 2017 that were not collected at the traditional random sites. Additionally, there were numerous rare species (i.e., unique and duplicate species) collected from 2013 to 2016 using random sampling that were collected at hot spot sites in 2017. Incorporating targeted sampling during bottom trawling did not improve species detection. Incorporating targeted sampling into survey designs yields improved efficiencies in both species detection and detection of rare species. This is especially true in instances where resources (i.e., personnel and funding) are limited, and habitat assessments cannot be conducted to inform a targeted or stratified sampling design by habitat type. Targeted sampling can improve species detection [5; 9] but determining areas to target may not be possible without prior knowledge of or adequate resources to determine habitats present. Using a random sampling design for several years to inform a hot spot analysis is an example of using an adaptive evaluation approach to sampling design, which has been shown to improve species detection [6; 26].