The current DAR marine monitoring program employs numerous different methodologies developed by DAR scientists in collaboration with NOAA, USGS and UH. Specific methods are used at study sites depending on the resource management concerns that DAR is looking to address, and include surveys of abundance of resource and herbivorous fish, smaller cryptic fish and recruits, urchins and larger mobile invertebrates, benthic habitat cover, coral health and biological diversity.
Routine marine monitoring has been a component of the Division of Aquatic Resources (DAR) (formerly the Department of Fish and Game) for over 50 years. Early efforts concentrated on using in-water visual assessments to measure resource fish stocks and changes to those stocks within marine protected areas and at artificial reef sites. For the past 15 – 20 years, efforts have been made to improve upon research methods, increase the frequency of surveys, expand the number of areas covered by assessments, and study changes associated with new management initiatives. As a result, today’s marine monitoring efforts are based on multi-faceted annual assessments of the coral reef ecosystem across a range of management zones. The current DAR marine monitoring program employs numerous different methodologies developed by DAR scientists in collaboration with NOAA, USGS and UH. Specific methods are used at study sites depending on the resource management concerns that DAR is looking to address, and include surveys of abundance of resource and herbivorous fish, smaller cryptic fish and recruits, urchins and larger mobile invertebrates, benthic habitat cover, coral health and biological diversity. Advances in technology have also allowed for broader use of GPS and digital photography and allowed monitoring information to be analyzed and displayed in a GIS format. This report outlines a few specific examples of how DAR’s monitoring program has been utilized to guide and evaluate current resource management efforts.
Monitoring of coral reef habitats on Maui began as early as 1993 at some locations around the leeward coast. When compared with the results of current reef monitoring, these long-term data sets have allowed for the identification and quantification of alarming trends at nearly all monitored reefs. Many sites have experienced a complete collapse of the coral community, as live coral cover dropped dramatically and reefs became dominated by invasive algae. The results of these monitoring efforts have been instrumental in helping the department identify a specific location were management action may help reverse the decline in reef habitat before it is too late. At the Kahekili reef monitoring sites in north Kā’anapali, Maui, coral cover was found to have declined from 55% in 1994 to 33% in 2006. This information, coupled with fish surveys suggesting reduced herbivorous fish abundance, helped guide the establishment of the Kahekili Herbivore Fisheries Management Area (KHFMA). The rules at the KHFMA prevent take of critical grazing fish and sea urchins and became effective in July 2009. The implementation of these rules was the first time in Hawai’i that fisheries management was employed specifically to help protect coral reef habitat. The creation of the KHFMA has also been critical in helping to increase public awareness of the many factors affecting our coral reefs and helping to drive land management policies towards reducing land-based pollution. Ongoing habitat and fish monitoring projects continue within this area in order to assess the effectiveness of the management efforts, and to guide future adaptive management.
ASSESSMENT OF LAYNET FISHING REGULATIONS
One of the objectives of the fish and habitat monitoring programs on Maui and O’ahu is to study ecological trends in areas where laynet fishing has been prohibited since 2007. The primary monitoring sites and methodologies employed on Maui and O’ahu under the standardized DAR monitoring program were developed prior to the implementation of laynet fishing restrictions in 2007, so additional sites and survey methods were developed to address this new management initiative. To that end, we added components to our protocols to place greater emphasis on herbivorous fish and urchins and to detect changes in dominant coral and algal species. On the Island of O’ahu, we are monitoring areas where laynet fishing was prohibited in relation to control sites where this fishing method is still permitted. One such area is Kāne’ohe Bay. Sixteen transect sites were established in the bay to cover fringing, barrier and patch reef habitats both inside and outside of the no laynetting zone. Sites were also selected in areas where the DAR Aquatic Invasive Species team is using urchins and the “Supersucker” to control invasive algae, and in the no fishing zone around Moku o Loe (Coconut Island). Research protocols were customized because of the unique habitat structure in Kane’ohe Bay, but include surveys of resource and herbivorous fish abundance and detailed benthic surveys to study trends in algal and coral cover. Additional survey sites have also been established to study ecological trends in shallow fringing reef habitats in areas such as Mamala, Hanauma, Waimanalo and Kailua Bays on O’ahu, and at seven sights on Maui. The Maui sites were selected and characterized based on the extent of past laynet fishing. Overall, these broadscale fish and habitat monitoring efforts should help evaluate the long-term effectiveness of the laynet fishing regulations.
In 1998, Act 306 resulted in the establishment of the West Hawai’i Regional Fishery Management Area. Resulting management actions included the designation of 9 Fish Replenishment Areas (FRAs) where aquarium collecting was prohibited. Combined with existing marine reserves, this action set up a network of marine managed areas making aquarium collection off-limits in 35.2% of the West Hawai’i coastline. In order to study the impacts of the FRA network, and of continuing aquarium fishing in areas remaining open to collectors, DAR and partner researchers from UH Hilo and Washington State University Vancouver initiated the West Hawai’i Aquarium Project (WHAP). Twenty-three permanent fish monitoring sites were established within representative locations at previously protected areas (MPAs), newly established FRAs, and areas allowing for continued aquarium collection (Open Areas). Since their establishment in 1999, these sites have been routinely surveyed 4 – 6 times per year. Over the 15-year period following the establishment of the FRAs, the size and value of the West Hawai’i aquarium fishery has increased moderately. There are currently 19% more aquarium permit holders and the number of marine animals harvested has increased by 52%. Even with the increase in overall harvest, WHAP monitoring data has provided unequivocal evidence of aquarium fish population increases within the FRAs and other areas along the West Hawaii coastline. This evidence is particularly clear for Yellow Tang, which comprises 82% of the total aquarium catch. Yellow Tang populations have increased by 72% in the FRAs, 29% in MPAs and 31% in the Open Areas (1999/2000 – 2014/2015 comparisons). These monitoring results have been instrumental in documenting the success of the overall FRA management approach, and importantly, they are helping to guide the West Hawai’i Fishery Council (WHFC) and DAR as they adaptively manage this important fishery for future sustainability.