|The Transect Line – February 2012
|Reef Check Spotlight: Why is Diver Monitoring So Important to Manage Reef Fisheries?
|By Reef Check California Director Dr. Jan Freiwald
Many species of fish gather together in one area to spawn and reproduce. Smart fishers can target these areas and times and reap a high catch rate. Unfortunately, this can lead to rapid over-exploitation of these fisheries due to the large number of mature (reproductive fish) removed from the population before they have a chance to reproduce. In addition, if only data from fish catch is used by managers — it is possible for a decline in population size to be hidden from the managers for some time. Therefore it is important for fisheries managers to have access to what is called “fisheries independent” data such as the monitoring results carried out by Reef Check divers. Reef Check data is fisheries independent because the actual number of fish on rocky reefs are counted — in comparison to “fisheries dependent” data such as total catch.
A recent study by Brad Erisman et al., (2011) documented this problem in two southern California fisheries- the barred sandbass (Paralabrax nebulifer) and the kelp bass (P. clahtratus). Both these species aggregate during spawning, and the commercial fisheries were closed in 1953 because of concerns of potential overfishing. But the annual catch from recreational fishing remained stable or increased over a 30 year period through the 1990s, apparently indicating no problems. In fact, the actual population sizes of these two species declined dramatically by about 80% during this period based on diver surveys of actual numbers of fish on reefs.
The fact that the catch remained the same for such a long time period is due to the fish being targeted at high density aggregations and therefore being caught in high numbers even if overall population density is declining. Since the majority of the annual catch of these species is landed during these spawning aggregations it creates the impression of a sustainable fishery. This effect is termed hyperstability, meaning that the fishery seems to be stable while in reality the populations are declining. The data based on the fishing effort and annual catch did not reflect the true signal of population decline. The authors state that fisheries dependent data “created the illusion that harvest levels for both species were sustainable and stock abundances were stable”. Based on this information, resource managers maintained the same catch levels and have not adjusted their management strategy because the true decline of the populations was hidden from their ‘view’.
This study demonstrates the importance of fisheries independent data collection to gain insights into the population dynamics of exploited species. Without diver surveys or other independent measures of population density or biomass, the decline of these two species in southern California would not have been detected. Reef Check is monitoring both of these species in southern California and is working with fishers in Baja to develop sustainable fisheries for other aggregating species, such as groupers found along the Baja peninsula. Unfortunately, many open-water fisheries are very difficult to directly monitor. The lack of fisheries independent data is one reason why 85% of the world's fisheries are considered overfished or have collapsed.
Erisman, B.E., Allen, L.G., Claisse, J.T., Pondella, D.J., Miller, E.F., and Murray, J.H. 2011. The illusion of plenty: hyperstability masks collapses in two recreational fisheries that target fish spawning aggregations. Can. J. Fish. Aquat. Sci. 68(10): 1705-1716.
|Reef Check California Update
|By Reef Check California Director Dr. Jan Freiwald
Once all our data from the previous year is entered in January we always have the joy of determining our “Golden Slate” winners. These are the volunteers who have completed the most transects in the previous survey season. This year, I am honored to present Dirk Burcham as the winner and Ted Sharshan as the runner up in Southern California, and Vincent Christian as the winner and Peter Ottersbach as the runner up in North/Central California. Since Dirk is a previous winner, he received a Golden Transect to add to his collection this year.
Dirk is also the holder of the lifetime record for most transects with 573 completed. Last year Dirk did 172 transects and Vincent did 46. All four volunteers have been working with us since the beginning of the program. It is long-time volunteers like these and the many others who have helped to grow the program and make Reef Check California what it is today. Only because of their dedication can we continue to monitor our rocky reef sites and consistently collect data that is used for marine management state-wide.
Each year the recipients of the Golden Slate are announced at our end-of-year volunteer parties. This year we had a great turnout at both parties at the Monterey Bay and Long Beach Aquariums, and attendees got a great behind-the-scenes tour of the aquaria.
Last year we had 244 active volunteers and we are looking forward to another successful year of monitoring and to seeing everybody in the water again. We are gearing up for our trainings over the next few months. So if you are a Reef Checker please go to https://reefdpd.wpengine.com/rcca/training_schedule.php and sign up for one of our recertifications or if you are not yet certified, take one of our trainings to join our group of volunteers and dive with purpose to make a difference in marine management in California.Comment on this article
|Volcano Poses Unique Threat to Montserrat's Coral Reefs
|By James Hewlett, Reef Check Montserrat Coordinator and EcoDiver Course Director
On January 6, 2012, a group from Finger Lakes Community College (FLCC) in New York arrived in the Caribbean nation of Montserrat to continue their work on a reef research project as part of the ongoing Research Integrating Molecular and Environmental Science (RIMES) program. The group was led by Professor James Hewlett, a Reef Check Course Director and Coordinator. Accompanying Hewlett as a Teaching Assistant was Ashli Roberts, a certified EcoDiver. Rounding out the team were students Courtney Stein and Barb Dagata, and Troy Depperman, Dwayne Daley, Oswald West, and Raphael White of Montserrat’s Green Monkey Dive Shop.
A rare streak of winter calm provided ideal conditions for conducting research and provided an opportunity for the team to organize a Reef Check survey. The team was able to add three new reef sites to the Montserrat survey program. The Reef Check data collected on Montserrat has been a valuable asset to the RIMES program and has been used in publications, consultant reports, and management recommendations submitted to the local government. It appears that the decline in hard coral cover measured over the past 10 years has stabilized and remains in the 8-15% range. Heavy fishing pressure, including pot fishing, continues to be a threat to the nearshore reef system on the leeward side of Montserrat. Of particular note was the addition of Montserrat to the growing list of Caribbean islands impacted by the invasion of Pterois volitans (Red Lionfish).
Montserrat’s reefs face an unusual threat due to its active volcano in the Soufriere Hills. Volcanic activity began in 1995 and continues to this day. A January and February 2010 collapse of the volcanic dome dropped more than 70 million cubic meters of hot ash and rock onto the landscape and out into the ocean on both the leeward and windward side of the island. Direct deposition of ash, increased erosion, and increased redevelopment activity has contributed to a substantial sedimentation load on Montserrat’s reefs. One of the primary objectives of the research program is to establish a monitoring protocol for all sources of sedimentation and ash deposition for each study site. While sedimentation and siltation sources are diverse and varied from site to site, sources of volcanic ash deposition can be categorized as either direct (pyroclastic flows and atmospheric deposition) or indirect (run-off/erosion, resuspension and redeposition). The Soufriere Hills volcano has been “quiet” with minimal dome growth since the 2010 collapses. This period of calm has contributed to a significant reduction in deposition of ash on Montserrat’s reefs.
Overall siltation and sedimentation rates on Montserrat’s reefs are believed to be very high due to the combined effects of intermittent deposition of volcanic ash following dome collapses and an above average sediment load due to erosion. Erosion in areas impacted by volcanic activity can be attributed to extensive deforestation, defoliation, and loss of vegetative cover. It is believed that sedimentation due to erosion has increased over the last five to seven years north of the exclusion zone due to the alteration of the landscape for development, road construction, and mining. This increased threat is exacerbated in northern areas of the island where there are regions of steep relief and soils that are erosive in nature. Using data from a variety of sources (sediment traps, rainfall and turbidity data, ash cloud data) the FLCC team has developed a six point estimate to assess frequency and load integrated over all sources of sedimentation. This data is then added to other measured sources of stress on Montserrat’s reefs in an attempt to quantify the effects of stress on the reef ecosystem. Utilizing the sedimentation data, the FLCC team is currently trending the robust Reef Check database from Montserrat in an effort to establish correlates of reef stress.
|New Trainers Certified in the Bahamas
| On February 1, 2012 a group of marine scientists from The Nature Conservancy (TNC), The Bahamas National Trust (BNT) and The Bahamas Department of Marine Resources (BMR) performed the first of what is hoped to be a series of Reef Check survey dives on Mike’s Reef off southwestern New Providence, Bahamas. The survey group members were Frederick Arnett and Jared Dillet of DMR, Ancilleno Davis of TNC, and Lakeshia Anderson, Lindy Knowles and Krista Sherman of BNT. With the exception of Mr. Knowles, the group had been previously trained in Reef Check methodologies and was participating in a Training of Trainers workshop with Reef Check Dominican Republic’s Dr. Ruben Torres.
Mike’s Reef is located 3.2 km off the southwestern coast of New Providence. The reef was chosen because it is a popular, well used site for recreational divers and receives daily visitors almost year-round. The site is also used for recreational and small scale commercial fishing. Mike’s Reef is located within the proposed Western New Providence Managed Marine Area and is an ideal site for comparison to other, less used reefs (e.g. marine reserves) within The Bahamas. Two surveys were completed using the Reef Check methodology.
Fish surveys showed that commercially important species (groupers, snappers and grunts) were in lower abundances when compared to non-target fish species (parrotfish and butterflyfish). These results are consistent with the current protection level of this area, which is non-existent.
Gorgonians were the most abundant Reef Check indicator invertebrate observed at Mike’s Reef along the transects. This may be due to high water flow-through in the area and the location of the transects on Mike’s Reef. Lobster abundance could be low due to subsistence or recreational fishing pressure. The low Diadema abundance observed during this study is typical of the region following the 1980s epidemic from which only shallow areas are beginning to recover. The other Reef Check indicator species are currently not of economic importance.
Even though 76% of the surveyed portion of Mike’s Reef consisted of non-living components, the low macroalgal coverage (due to grazing pressure by high parrotfish densities) could mean that there is suitable area for coral recruitment. However, live hard coral cover was 10% suggesting that there may be other factors preventing coral recruitment to the area not related to substrate type.
Impacts related to coral bleaching and disease were low (<5%). Anthropogenic impacts were also low (<1 on the 0-3 perceived impact scale) despite the fact that the area is heavily used by recreational divers. This may be indicative of local dive tour operator management (e.g. active trash removal and mooring buoys) of the area.
This was the first complete Reef Check survey to be conducted within the proposed boundaries of the South West Marine Managed Area in New Providence, Bahamas. The data presented in this report provide baseline information on the status of coral reef health in the area surveyed on Mike’s Reef. Additional surveys are required to document changes in the area and obtain a more detailed understanding of coral reef health.
In addition to completing the surveys, a coral reef monitoring plan was drafted, indicating the minimum number of Reef Check surveys to be conducted throughout The Bahamas after Reef Check teams have been established in each location. Reef Check is intended to supplement ongoing coral reef monitoring in The Bahamas and it is recommended that detailed coral reef monitoring using a modified version of Reef Check or the AGRRA protocol be conducted in key areas every 3-5 years.
|Recent Study in DR Shows Benefits of MPA Management in La Caleta
| FORCE (Future of Reefs in a Changing Environment) recently released a preliminary report on their 2011 survey of reefs in the Dominican Republic. Their study showed that reefs in the Dominican Republic may improve if regulations are set similar to La Caleta, an area protected from fishing and anchoring, and co-managed by Reef Check Dominican Republic since 2007.
The FORCE project uses an ecosystem approach that links the health of the ecosystem with the livelihoods of dependent communities, and identifies the governance structures needed to implement sustainable development. The overall aim of FORCE is to provide coral reef managers with a toolbox of sustainable management practices that minimize the loss of coral reef health and biodiversity.
Reef communities were surveyed at 10-15m depth in 15 locations during June 2011.
The highest mean coral cover per site was found at La Caleta (43%) while the lowest coral cover was observed at Sosua (10%). La Caleta also had the highest number (46) and density (8.2 individuals per m2) of coral recruits.
Over 4 kilometers of reef were surveyed for fish. Cayo Arena had the highest fish abundance, while Sosua had the lowest. However, the mean fish species richness was highest in La Caleta (average of 29 species per transect), with the lowest again in Sosua (9 species per transect).
Overall, fish communities were healthiest in protected areas such as La Caleta or remote areas such as Cayo Arena. La Caleta also had the healthiest bottom communities, with high coral cover and high sponge diversity. The only lobster and conch counted in the Dominican Republic were also within La Caleta Reserve.
Click here to view the full report.Comment on this article
|Reef Check Save the Reefs, Save the Oceans Gala: September 8, 2012
This year's Save the Reefs, Save the Oceans Reef Check Gala will be be held September 8, 2012 at the Jonathan Beach Club in Santa Monica, California. The evening will recognize the contributions of our “Heroes of the Reef” each having demonstrated an exemplary commitment to ocean conservation.
Sponsorship opportunities are available. We are also looking for donated items for our live and silent auctions. Please contact firstname.lastname@example.org or 1-310-230-2371 for information.
Proceeds from the gala will fund educational programs for children and the conservation of tropical coral reefs and California rocky reefs.
Details on the 2011 gala can be found at https://reefdpd.wpengine.com/events/gala2011/
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