In aquatic ecosystems, fish, reptile, and amphibian species will be negatively impacted by climate change. In New Jersey, air temperatures are predicted to increase, and precipitation extremes are expected to increase as well. This translates to more intense flooding, droughts, and intense precipitation events that will alter habitat, promote crowding, increase competition, physiological stress, and mortality of freshwater fish populations. Fish, like Brook Trout, that require coldwater habitat are expected to lose habitat as water temperatures increase and will be replaced by warmer-water tolerant species.

Temperature Impacts

Climate change may ultimately have the greatest impacts to the future survival of native Brook trout, as climate change scientists are predicting mean annual temperatures to increase by approximately 4.5°C in northeastern United States.  However, coldwater habitat in many NJ streams have shown their ability to be resilient and buffered against the immediate impacts of air temperature change due to the thermal inertia of water and the effects of groundwater influence. In 2018 and 2019, results from a Fish and Wildlife study to determine resiliency of Brook Trout habitat found models with a projected air temperature increase of 3℃ (and assumed groundwater sensitivity of 0.66) predicted 36% of sites (30 out of 83 within the stream temperature monitoring network) containing Brook Trout, would no longer have suitable temperatures due to air temperature increase (Figure below).

Sites with very cold stream temperatures (i.e. strong groundwater influence) may be strongholds worth identifying as they are proving to be resilient even in the face of intense urbanization as analysis of stormwater impacts on wild trout streams has recently shown.

DEP’s first scientific report on climate change summarizes the current state of knowledge regarding the effects of climate change on New Jersey’s environment to inform state and local decision-makers as they seek to understand and respond to the impacts of climate change. The report, found here, identifies and presents the best available science and existing data regarding the current and anticipated environmental effects of climate change globally, nationally, and regionally.