NATIVE STREAM FISH SURVEY, KALALAU STREAM, NA PALI KAUAI
Kalalau Valley is located on the northern shore of the island
of Kauai within the spectacular coastal area of Na Pali. The Na
Pali area has long been recognized as one of Hawaii's most
important biological, cultural, and recreational wilderness
reserves. Rapidly increasing negative human-induced impacts on
this unique landscape are occurring and intensified by
unregulated access by hikers and commercial tour boat activities.
Large unchecked feral goat populations also add significantly to
watershed erosion and resultant degradation of Kalalau stream.
This survey was initiated to i) collect baseline data on
native stream fish populations in Kalalau stream and ii) to
develop protocols for the use of Geographical Information System
(GIS) applications in implementing biological surveys in the
State of Hawaii.
The GIS was used for inventory, managment and spatial analysis of the field survey data. The GIS for streams was created from the USGS 1:24,000 DLG files. These files contain primary as well as all secondary and tertiary streams in the same layer. In this study, GIS was used to aggregate Na Pali streams into major systems based on their watersheds.
All of these streams are found within remote valleys on the
northern coast of Kauai and accessible by a hiking trails only to
In this day-long survey (July 1992), six sites were sampled using underwater visual census (Kido, In Press). GIS aided in the identification of sampling sites to provide enough differentiation in slope, terrain, and canopy. Sampling sites are marked on the map as S1 (sea-level - 0 to 5m elev), S2 (10 m elev), S3 ( 72 m elev), S4 (157 m elev), and S5 (233 m elev), S6 (294 m elev).
While biomass data for invertebrates and algae were also
collected in the survey, only data comparing densities of native
gobiod fishes are presented for this demonstration.
The survey showed distinct differences in overall fish densities and species composition along an elevational gradient from sea-level to 294 m elevation. Fish were not observed above 294 m and overall densities decreased from high to low elevation. Sicyopterus stimpsoni ('o'opu-nopili) was most abundant from sea-level to 10 m elevation while Lentipes concolor ('o'opu-alamo'o) was most abundant from 72 m to 157 m elevation. Awaous guamensis ('o'opu-nakea) was relatively rare in Kalalau stream and generally confined to lower stream reaches. The native eleotrid, Eleotris sandwicensis ('o'opu-akupa), was only found near sea-level in very low density. Open the graph on the Kalalau site map to view bargraphs of the data.
Study Sites and Maps