Pacific Islands Stream Monitoring Protocol: Fish, Shrimp, Snails, and Habitat Characterization

Brasher, Anne; Jones, Tahzay; Farahi, Anne; Miller, Matt; Kozar, Kelly

Throughout the world, freshwater ecosystems are considered to be among the most vulnerable systems. In the isolated Pacific islands there are a relatively small number of native freshwater species, which are mainly endemic to these locations (found nowhere else in the world). These species are characterized by an amphidromous lifecycle; reproducing in the stream, with larvae drifting to the ocean and eventually returning to a stream as juveniles and spending the remainder of their lifecycle there. Throughout the region, native flora and fauna face significant threats from species introductions and habitat destruction. The National Parks in the Pacific Island Network (PACN) protect some of the last relatively pristine stream systems. Monitoring based on this protocol: Pacific Islands Stream Monitoring: Fish, Shrimp, Snails and Habitat Characterization, will provide park managers with some of the information necessary to understand status and trends in biotic integrity within park stream systems. Vital Signs are physical, chemical, and biological elements and processes of ecosystems that are selected to represent the overall health or condition of park resources, known or hypothesized effects of stressors, or elements that have important human values. Two vital signs associated with freshwater ecosystems were identified by the PACN network: Freshwater Animal Communities—Streams and Freshwater Animal Communities—Anchialine Pools. This protocol is specific to stream systems and a separate protocol is being developed for anchialine pools. The Freshwater Animal Communities: Streams Vital Sign is closely linked with the Water Quality Vital Sign, and monitoring efforts will be conducted in tandem to enhance the value of the data collected. The Pacific Islands Stream Monitoring Protocol will be implemented in four PACN parks: the National Park of American Samoa in American Samoa, War in the Pacific National Historical Park in Guam, Haleakala National Park in Hawaii, and Kalaupapa National Historical Park in Hawaii. This protocol is designed to address two monitoring objectives: 1) Determine long-term trends in population distribution and abundance, and community composition of freshwater fish and invertebrates (including snails and crustaceans) and 2) Quantify associations among stream animal communities (fish and invertebrates) and their habitat by correlating physical and chemical habitat measures with observed species distribution and abundance. This protocol employs a split-panel design with both fixed (sampled every year) and random (new each year) stations that are sampled annually. This design provides both status and trend information, and enhances the ability to use the data to conduct trend analyses. This design also maximizes the statistical power to detect change over time by providing the ability to conduct parameter corrections based on repeat analyses. Both native and introduced fish, shrimp, and snail abundances will be monitored at selected sites along each stream. In addition, quantitative and qualitative physical habitat information will be recorded. Water quality and discharge will also be measured at each sampling station; methods are described in a separate protocol.

Pacific Islands Stream Monitoring Protocol: Fish, Shrimp, Snails, and Habitat Characterization

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