Date of Award
Doctor of Philosophy (PhD)
College of Science and Mathematics
Earth and Environmental Studies
Thesis Sponsor/Dissertation Chair/Project Chair
Paul A. X. Bologna
Joshua C. Galster
Scott L. Kight
Shawn M. Crouse
New Jersey supports reproducing populations of three lotic salmonids. Only Brook Trout (Salvelinus fontinalis) are native and until approximately 100 years ago, were found in abundance throughout the northern part of the state. Presently, native populations have been documented in 115 streams or stream sections and declines are thought to be in response to anthropogenically originated environmental stressors. To evaluate the deterioration extent and assess numbers of breeding non-native Brown Trout (Salmo trutta) and Rainbow Trout (Oncorhynchus mykiss), comparisons are made between sets of historical (1968-1977) and modern (2001-2010) young-of-the-year presence/absence and abundance data and several geologic and land use/land cover characteristics hypothesized to influence species’ occurrence. The range of reproducing Brown Trout populations have expanded, while groups of Rainbow and Brook Trout, as well as the overall amount of non-trout water have all decreased slightly. Results show that land use and land cover catchment value thresholds exist at < 12% agriculture, < 22% barren and urban, > 64% wetland and forest, and < 4-6% impervious cover to allow for natural Brook Trout reproduction. Values for Brown Trout reproduction include < 14% agriculture, < 27% barren and urban, > 58% wetland and forest, and < 5-7% impervious cover. Additionally, a previously undocumented Brook Trout metapopulation has been discovered with abundance estimates suggesting that a flourishing, reproductive and viable population is being maintained. Also, observed movement between connected waters allows for gene flow and overall isolation may permit the existence of one of New Jersey’s remaining relict Brook Trout groups. Conservation of the once endemic native species has become a regional priority and a review of current lotic salmonid management strategies has identified some practices that may undermine protection efforts. Suggestions to reverse declines and bolster unique populations include: 1) establishing a ‘Wild Native’ angling regulation, 2) creating stricter land use directives to support more natural flows, 3) curtailing or cessation of domestic salmonid stocking at larger catchment levels, 4) developing hatchery operation expansion to include indigenous origin fish, 5) removal of non-native fish from favorable standing within the State’s Wildlife Action Plan, and 6) obtaining new or reallocating current funds to support more research.
Diglio, Luke J., "An Assessment of New Jersey Trout Production Systems : a Movement Towards Sustainability" (2015). Theses, Dissertations and Culminating Projects. 76.