Protecting Herbivorous Fish to Conserve Cayman Island Coral Reef Biodiversity

Contents

2 Contents 3 Acknowledgements 4 Introduction 4 Darwin Initiative 4 CCMI 5 The Cayman Islands 6 Project Description 8 Results - - Benthic Surveys - Species Descriptions - The dominant algae in the Cayman Islands - The fish species that consume them/ Feeding assays & fish observations - The fishes that scrape turf algae - Fish biomass - Fish diet – results from stable isotope analysis - Movements - Fishing pressure - Focus groups

26 Recommendations & Future Directions

30 Summary

Acknowledgements

CCMI would like to thank the following people for their invaluable assistance throughout this project: Richard McElhannon, Mark Akers, Brac SCUBA Shack, Simon Wicker, Kendall Messias, Darvon Bodden, Adam Jackson, Tom Sparke, Noelle Helder, Stephanie Macdonald, Gilman Ouellette, Kelly Forsythe, Lindsay Spiers and Ashly Carabetta.

Introduction

The Darwin Initiative

The Darwin Initiative is a UK government grants scheme that helps to protect biodiversity and the natural environment through locally based projects worldwide. Darwin Plus (also known as The Overseas Territories Environment and Climate Fund) provides funding for environmental projects in UK Overseas Territories as well as fellowships for UK Overseas Territories (OT) Nationals to increase their knowledge and ability to meet long-term strategic outcomes for the natural environment in UK Overseas Territories.

The Central Caribbean Marine Institute

CCMI is a not-for-profit organization founded in 1998 to protect the future of coral reefs, envisioning a world with vibrant oceans and healthy coral reef ecosystems. We seek to be the Caribbean’s premier marine research institute by delivering cutting edge research, transforming conservation strategy and developing education programmes of excellence – discovering and promoting real solutions to declining ocean health. Our plan is to invigorate key species and understand key ocean processes that drive reef resilience. We support early career scientists who are innovating ways to improve coral reef health. We are transforming conservation strategy and work to inspire the change that is needed to achieve our mission. CCMI are pioneers in the region working to reverse the declines of coral reefs.

The Cayman Islands

The Cayman Islands are a British Overseas Territory comprised of three limestone islands located at 19.3133° N, 81.2546° W, just south of Cuba and north-west of Jamaica. Grand

Cayman is 197 km2 and is the largest and most developed of the three Islands, Little Cayman and Cayman Brac are collectively known as ‘The Sister Islands’ and are located approximately

120 km east and are 29 km2 and 38.5 km2, respectively. In 2017 the population of the Cayman Islands was 63 415 people, of whom 96% live on Grand Cayman (CIDESO). 56.6% of the population are Caymanian, the remainder are ex-patriates who primarily come from Jamaica, America, Honduras, The Philippines, the UK and Canada.

The coral reefs that surround the Cayman Islands are an important resource for the country for multiple reasons. A recent report valued storm protection on Grand Cayman alone at $5 million USD per year and reef fishing in the country at USD2.3M per year (Wolfs Company, 2017, The Economics of MPA Expansion in the Cayman Islands). The same report valued the revenue generated by the marine environment from tourism at $69 million per year (Wolfs Company, 2017). In the first six months of 2016, 881 929 cruise ship passengers arrive to the Cayman Islands, spending 94.6M USD, 41.6% visited the reef. In that same time, over 200 000 stayover visitors arrived, spending 316.6USD, 72.1% visited the reef (Cayman Islands Department of Tourism Visitors Exit Survey, 2017). Finally, Plexaurella homomalla, a type of gorgonian and one of many reef species used in medicine and cosmetics, is being harvested in the Cayman Islands so is also generating revenue for the country (Wolfs Company, 2017). Therefore, any loss in these services could be financially costly for the country and could have severe consequences for the infrastructure on the island.

Figure 1: Map of the Cayman Islands. 96% of the population live on Grand Cayman, the largest and most developed of the three Cayman Islands (197 km2). Little Cayman and Cayman Brac are collectively known as ‘The Sister Islands’ and are located approximately 120 km east (and are 29 km2 and 38.5 km2, respectively).

Project Description

Coral reef health relies on dynamic interactions among key functional groups of organisms. Disruptions to the roles these taxa play (e.g. fish, coral and algae) can lead to changes in community structure with negative implications for coral reef biodiversity. Algae play important ecological roles in reef systems, but as excellent competitors for space certain species can compromise coral growth and/or larval recruitment. A critical process in regulating the balance between coral and algae is herbivory. A loss of herbivorous fishes due to overfishing has resulted in shifts is community structure from coral to algal dominated systems, thereby eroding overall coral biodiversity.

Currently, there is limited management, or protection, of herbivorous fishes under the Cayman Islands National Conservation Law; a draft fish conservation plan is proposing to improve protection of all fish. The work proposed in this project will identify and assess movement patterns of functionally important herbivores that maintain coral reef community structure as

6 well as estimate current fishing pressure. This project aimed to ensure that effective protection measures are implemented and biological diversity and coral reef health are conserved; thereby addressing OT Government priorities of promoting sustainable fisheries and improving the protection and management of the marine environment.

The primary objective of this project was to promote the sustainable use of coral reefs and provide support for targeted management of herbivorous fish species. As such, we determined the key herbivorous fish species, quantified the impact they have and assessed the fishing pressure they currently face. From this we were able to draft a chapter on herbivorous fishes for the National Coral Reef Biodiversity Action Plan.

Herbivorous fishes may be a sizeable part of the reef fishery in the Cayman Islands, in which case it may be very unpopular to ban fishing of the whole family (as has been done elsewhere Kramer et al., 2015). Instead, obtaining a species-specific understanding of the role of parrotfish and other herbivores on the reef may permit targeted species-specific management plans. This could allow fishermen to continue their trade while also protecting the key species on Cayman reefs.

Results

Benthic Surveys

To determine the quantity and composition of macroalgal cover on the reefs of Cayman, we photographed the benthos from 10 transects per site at five sites on the north side of each island in April 2017. Results showed coral cover was between 9% and 12% across the three islands, while macroalgal cover was between 40% and 53%. Of this macroalgal cover, the majority was Dictyota spp. (> 20 %), followed by Lobophora variegata (12% to 16%) and then on Cayman Brac Microdictyon marinum was the third most common species (12%). Turf algae was 2% to 3% across the three islands.

Picture 1: Two Permanent Plots Showing Algal Cover on the Reefs of Cayman

The prevalence of Dictyota spp. and Lobophora variegata are very much in keeping with the remainder of the region (E. D. de Ruyter Van Steveninck and R. P. M. Bak, Mar. Ecol. Prog. Ser. 34, 87 (1986); Mumby et al 2005; Lesser and Slattery 2011; Gaubert et al 19 – Scientific Reports) where total algal cover is 40% of the reef (AGRRA database).

Species Descriptions

Lobophora variegata (J. V. Lamouroux), henceforth Lobophora, is a corticated, foliose, brown macroalga (Dictyotaceae, Ochrophyta) has a circumtropical distribution (De Ruyter et al. 1987 MEPS), broad depth range (Littler et al. 1986, Lesser and Slattery 2011) and is commonly found on tropical coral reefs in the Caribbean and in the Pacific (de Ruyter Van Steveninck & Breeman 1987 – MEPS; Vieira et al 16 Scientific Reports).

Dictyota (J. V. Lamouroux) is another common genus of corticated, foliose, brown macroalga (Dictyotaceae, Ochrophyta) that is also found on tropical and subtropical reefs worldwide (De Clerk et al 2006 J Phycol). It has a branching morphology that exhibits considerable variability, meaning that species level identification in the field is problematic (Phillips 1992; De Clerk & Coppejans 99 Phycologia).

Microdictyon marinum (Bory de Saint-Vincent) – henceforth Microdictyon – is a coenocytic, green macroalga (Anadyomenaceae, Chlorophyta) which grows in a net-like structure that can form a thick cover over the benthos (Figure S1). While it is known to bloom in the Bahamas (Lapointe et al. 2004 JEMBE; Easson et al. 2014 MEPS), it is not frequently reported from elsewhere in the Caribbean and appears to be uncommon in the region (Littler & Littler 2002, the algae bible).

Picture 2: Closeup of the Three Dominant Macroalgae on the Reefs of Cayman

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Microdictyon on Cayman Brac

The distribution and dominance of Microdictyon on Cayman Brac is unusual because it grows to dominate the north side of the island in summer, yet is absent from the south of the island and from the rest of the country. Percent cover from permanent plots that were established deep (between 15m and 30m depth) and shallow (5m to 12m depth) on the north and south of the island show it grows to cover 60% of the reef in summer (these data are from June, Picture 1 & Figure 3). Our concern with this anomaly in the Cayman Islands was that it might result from a source of pollution or from a lack of herbivores, so we measured both these factors in winter and summer.

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Figure 3: Algal Percent Cover on the North (left panel) and South (right panel) of Cayman Brac

Not much is known about this species because it is so rare in the region, so experiments were conducted to ascertain whether it was harmful to corals. If it was benign then it would not present the same stress to corals as Dictyota and Lobophora and so there would be no need to control it. Results are presented in Appendix A.

Feeding Assays and Fish Observations

Having identified the most abundant macroalgae, we then observed fish feeding and ran feeding assays with the three dominant macroalgal species to determine which fishes consumed the most macroalgae. In total, we conducted over 34 hours of observation of 105 fish from eight species counting the bites from the benthos. We also ran 44 hour-long trials using Dictyota, Lobophora and Microdictyon across two sites and two feeding periods (morning and midday).

The results from both these methods yielded parallel results. From the observations, we found the Bermuda chub (Kyphosus spp.), blue tang (Acanthurus coeruleus) and redband parrotfish (Sparisoma aurifrenatum) consumed a significantly higher proportion of total macroalgae (85%, 35% and 41%, respectively) than all other species we observed. (For the other species, macroalgae was less than 11% of the bites consumed.) Of this total macroalgae, the Bermuda chub consumed the most Dictyota (78% of total bites from the benthos), followed by the blue tang and redband parrotfish (14% and 16%, respectively). The blue tang consumed significantly more Lobophora than any other species (21% of total bites of the benthos), while Lobophora constituted less that 6% of the bites for the other species. Other macroalgae (predominantly Halimeda but occasionally also Sargassum) comprised 18% of the bites for the redband parrotfish which was significantly more than all other species. (Other macroalgae were less than 5% of the bites of other species, Figure 3.)

These results are not due to unusually high densities of these species. Indeed, the densities recorded at our sites are in keeping with those reported by AGRRA in 2018 for these families

(we recorded 21.2/100m2, 7.9/100m2 & 0.6/100m2 for parrotfish, surgeonfish and Bermuda chub respectively, while densities from AGRRA in 2018 were 24.3/100m2, 11.9/100m2 & 0.6/100m2 for parrotfish, surgeonfish and Bermuda chub, respectively; AGRRA database, 2018).

Turf algae was a noticeable proportion of the bites of all species except for the Bermuda chub. (1% of total bites). However, the species most responsible for removing turf from the reef were the queen parrotfish and the stoplight parrotfish (94% and 68% of total bites of the benthos, respectively).

Figure 4: Percentage of Bites Taken of Macroalgae, EAM & Epiphytes (n = 9 - 20). Fish were followed for 20 minutes counting number of bites taken off the benthos, distinction was made between EAM bitten from reef surface indicated in black, epiphytic growth represented in dark grey, and consumption of macroalgae: Dictyota (blue), Lobophora (orange) and other macroalgae (green). Bites that could not be reliably identified are in pale grey. Letters indicate homologous subsets from analysis of bites of total macroalgae using Permutations ANOVA.

Picture 3: The Three Main Consumers of Macroalgae on the Reefs of Cayman

The results from our feeding assays agree with these observations in that, from the 44 hour-long trials using three algal species and at two sites and two feeding periods, only three fish species

13 were observed feeding from the ropes with any regularity: the Bermuda chub, blue tang and redband parrotfish (Figure 4). This pattern was despite seven to ten herbivore species being present during the trials, including the ocean surgeon and five species of parrotfish at both sites.

Picture 4: Experimental Arrangement for Feeding Assay Experiments. The alga was secured within the strands of a three-ply rope and filmed so that diver presence did not influence fish behaviour.

The number of bites taken by each species per hour is less indicative of impact on the reef than the quantity of algae consumed by each species. Therefore, to estimate the quantity of algae consumed by each species we calculated the grams consumed per bite for the three main consumers and multiplied this by the number of bites counted in the videos. We found no significant differences in grams consumed by the three main herbivores at either site or for any macroalgal species.

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e 0 0 b d g b d g b d g Chub Redband Tang Chub Redband Tang M u an an u an an u an an Ch edb T Ch edb T Ch edb T R R R Dictyota Lobophora Dictyota Lobophora Microdictyon Figure 5: Mean Bites Taken (upper panel) and Grams Consumed (lower panel) from Site One (left) and Site Two (right) for the three key herbivores, the Bermuda chub, redband parrotfish and blue tang surgeonfish. The number of bites was counted from 44 hours of feeding assay videos. X indicates Bermuda chub were not seen at site two.

It should not be surprising that a species of Kyphosus was a frequent consumer of brown macroalgae. In 1967 Randall reported that the stomach contents of two species in the Caribbean were 100% brown macroalgae and 99.5% brown and red macroalgae (n = 6 and 19, respectively, Randall 1967). Further, the family Kyphosidae have long been recognised as important browsers in the Indo-Pacific (Clements & Choat 1997; Green & Bellwood 2009; Knudsen & Clements 2016). However, they are often not considered as such in the Caribbean. Indeed, many papers omit them from the guild of herbivorous fishes entirely (for example see: Mumby 2006; Kramer et al. 2017; Suchley & Alvarez-Filip 2017).

Fish Biomass

Now that we had ascertained which are the dominant macroalgae and also which fish species consume them, we were able to investigate the biomass of these key herbivores across the reefs. To investigate any potential changes in fish density over time, we surveyed the same sites CCMI had visited in 1999. These results are in the Healthy Reef Report, published by CCMI in 2019. In addition to this, we also surveyed fish biomass in winter and summer to assess changes with season. These surveys were also conducted on the north and south sides of Cayman Brac, to determine whether fish biomass explained the pattern of Microdictyon distribution. Data shown is from the surveys of Cayman Brac (Figure 6). We also found no significant differences in herbivore biomass between the north and south of Cayman Brac, however we did discover that the biomass of Bermuda chub is five times greater on both sides of the island in summer.

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Figure 6: Fish Biomass of the Three Key Herbivore Species on the North and South Side of Cayman Brac in Winter & Summer

Stable Isotope Analysis of Diet

While feeding assays and observations both showed that Kyphosus spp. (Bermuda chub) consumed macroalgae, this did not tell us the full range of their diet. Additionally, not knowing which or how many species of Kyphosus are in the Cayman Islands, it is very possible that we only observed one species in Little Cayman and that other species reside elsewhere which may have different diets. Analysis of nitrogen and carbon stable isotope ratios can provide this information. Stable isotope analysis (SIA) is widely used to provide insight into organisms’ diet and trophic position and in this situation is preferable to stomach content analysis for two important reasons. Firstly, killing the animal is not necessary for SIA so this avoids unnecessary loss of an important herbivore. Secondly, rather than providing information on diet from a single time point, SIA provides an integrated signal over weeks to years (depending on the tissue). Thus, we can obtain information at a higher resolution because SIA can provide information on the degree of omnivory and the relative importance of different food sources to an organism (Post 2002).

Kyphosus spp. exhibit a range of diet from exclusively herbivorous (trophic level 2), omnivorous (level 2.5) to exclusively carnivorous (level 3, Figure 7). Results for Kyphosus spp. from elsewhere in the Atlantic signify the genus is primarily herbivorous (Ferreira & Goncalves 2012, Lamb et al. 2012, Mendes et al. 2018). The majority of individuals sampled from the Cayman Islands concur because they are between level 2 and 2.5 (Figure 7). A degree of ominvory is expected because this genus has been reported to consume detritus (Ferreira & Goncalves 2006) and because epiphytic invertebrates residing on macroalgae may be consumed along with the algae. However, the very high values at Governor’s and by the Turtle Centre (see Figure 8), suggest they are not consuming algae but are fully carnivorous, which is not their diet under non- manipulated conditions. We speculate those fish are feeding on anthropogenic food sources instead. The fish caught by the Turtle Centre were seen feeding in the sewage outfall and it seems this may constitute the majority of their diet. Similarly, Governor’s beach is a popular tourist area so it is possible the fish there are consuming primarily bait (squid, soldier crab, squeezy cheese?). The result from Sunset House is from only one fish, so is of limited use and may not be indicative of the population. Considering that Kyphosus spp. are one of the key

17 herbivores in the Cayman Islands, it would not bode well for the reef if too many were feeding exclusively on bait.

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Figure 7: Trophic Position of Kyphosus spp. from Stable Isotope Analysis. The blue line indicates the trophic position of herbivores and the red line indicates the trophic position of carnivorous primary consumers. Blue bars denote the diet of Kyphosus spp. is herbivorous to omnivorous, Orange bars denote those fish are omnivorous to carnivorous, while red bars denote those fish have a carnivorous diet.

Figure 8: Sites of Kyphosus spp. Sampling on Grand Cayman. As in Figure 7, blue denotes the diet of Kyphosus spp. is herbivorous to omnivorous, orange denotes those fish are omnivorous to carnivorous and red denote those fish have a carnivorous diet.

The other notable finding that came from SIA was the distinction in diet between those fish with yellow lines and those without. We found the former were predominantly herbivorous, while the latter were more likely to consume animal matter. This difference in diet, plus the morphological difference could indicate these are separate species.

Figure 9: Picture of Kyphosus spp. Without (Left) and With Yellow Stripes. It remains to be determined whether these are different species.

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Figure 10: Trophic Position of Kyphosus spp. With and Without Yellow Lines from Each Island. Those fish with yellow lines eat a herbivorous diet, while those without fed higher in the food chain and consumed a more omnivorous diet, especially on Grand Cayman.

Observations of Herbivore Movements

We followed 18 schooling and 17 solitary individuals of Kyphosus spp. for 10-minute observation periods during the summer 2019 and tracked their movements using a handheld GPS. The average distance moved for both categories was 16.5 metres which indicates high site fidelity and suggests they may not be ‘roving herbivores’ throughout the year. It would be useful to determine how these movement patterns change seasonally and with species because this will influence how the genus impacts the reef. Higher site fidelity may denote more localised herbivory at a site and thus a more sustained, positive impact on the reef.

Fishing Pressure

The next step was then to investigate the fishing pressure on these key herbivores and to accomplish this we used two methods so that we could verify the results. Firstly, we conducted interviews with the fishing community, secondly, we quantified the catch for sale at landing sites.

Picture 5: Catch for Sale at Landing Sites on Cayman Brac. The species most frequently seen for sale was the ocean triggerfish (‘turbot’), the only herbivore recorded was the spotlight parrotfish (Sparisoma viride). The three key herbivore species were never recorded for sale during our observations.

In total we conducted 19 interviews with fishermen from a range of nationalities who self- identified, including Caymanian, American, Jamaican, Honduran, Guyanese, and Filipino. Of the three islands, most interviewees reside on either Little Cayman or Cayman Brac. Interviewees represented diverse occupations including government, marine management, non-governmental conservation, professional fishing guides, dive masters, and law enforcement. Although the preliminary sample size is small, our qualitative approach to data collection and analysis illuminates salient meanings based on their experiences and interactions with reef ecosystems for people who live and work across the Cayman Islands.

Initial findings illustrate a strong participation in offshore fishing among interviewees. While far more descriptions of offshore fishing were reported than shore-fishing, more species were described as captured during shore- and reef-fishing (n=17) than off-shore fishing (n=6). For example, from the shore or reef, interviewees reported catching: - Snapper (mutton; mahogany, schoolmaster) - Parrotfish (stoplight, queen, princess, yellowtail (white); midnight; rainbow) - Grouper (rock) - Surgeonfish (doctorfish) - Chubs - Jacks (bar, horse-eye, yellow) - Triggerfish (turbot) - Conch - (No grunts, angelfish, or filefish were reported as caught)

From offshore, interviewees reported catching: - Wahoo - Tuna - Dolphin (mahi mahi) - Marlin - Barracuda

Focusing on herbivorous reef species, interviewees described a mix of aiming and bycatch, as well as keeping or releasing: - Parrotfish (sometimes caught from shore and kept, sometimes released) Species aimed for and kept: midnight, spotlight, princess Species that were bycatch but kept: yellowtail (white), rainbow - Surgeonfish: mostly bycatch and mostly released - Bermuda Chubs: not aimed for but sometimes kept and sometimes released

Whether catching and consuming fish from shore, reef, or offshore, the benefit of food/protein to physical health was commonly described. In terms of cultural ecosystem services and benefits, interviewees described a range of interactions with nature while fishing from shore or on water that they perceived to be beneficial to dimensions of their well-being. For example, fishing on water was commonly described as an environmental space that enables cultural practices like playing and exercising that deliver benefits to one’s identity, capabilities, and experiences. Interestingly, this was reported with reference to one’s own excitement and escape while fishing, as well as economic benefits derived from one’s job in guiding someone else’s fishing

22 experience. Offshore fishing was often described as a place and practice that enables playing, exercising, expressing, caring, gathering, consuming, viewing, relaxing, learning, and socializing with many benefits such as of excitement, discovery, knowledge, inspiration, escape, and relationship-building. Shore-fishing was described in more practical terms – specifically, for gathering and consuming fish, while occasionally relaxing and socializing to escape a hectic workday.

The results from our analysis of catch sold at landing sites corroborated the results from these interviews. From the 110 visits to the nine popular fishing locations on Cayman Brac, fishermen were present with their catch 44 times with a total of 181 fish recorded. Of these the triggerfish, most especially the ocean triggerfish (turbot) was the most common genus caught (34% of all fish caught were triggerfish). Snapper were the second most popular (30%) and then the bar jack (12% and the only jack recorded). Of all fish caught, the only parrotfish recorded was the spotlight (Sparisoma viride): 12 individuals were recorded on two visits (5% of total catch). No surgeonfish and no Bermuda chub were seen during any of our visits.

From these responses we see that the three key herbivores are not under pressure from fishing at this time. We can also understand that fishing is a very important part of life for the people who reside in the Cayman Islands, so care should be taken when imposing legislation that curtails this activity. It would be unwise to impose pre-emptive restrictions on catching these species, because it would not impact the fish populations and would only upset and alienate the fishing community who (from personal communication) already feel persecuted. The approval of MPA expansion reduces the area available for fishing and further (unnecessary) regulations may reduce compliance with existing legislation.

Focus Group Meetings

The final element of this grant was communication with the community through the establishment of focus groups. This was to create the opportunity for dialogue with the community, to share our findings with the residents of the Cayman Islands and to hear their responses. We were particularly interested to learn what the community thinks is important and what they suggest should be done in response to our results. In total 10 meetings with 30 people on Grand Cayman and 43 people on Cayman Brac were held. Members of the government, the deputy premier, resort managers, dive professionals, fishermen, members of the national trust & the general public participated. The key findings are as follows.

80% of respondents said that the changes on the reef directly affect them. The two reasons given most frequently were that these changes affect their enjoyment of the reef and secondly, that they affect the tourism sector and economy of the country. 79% of respondents made suggestions and many had multiple ideas. The most common suggestions were the reduction of fishing, education, more research and the manual removal of algae. Other recommendations were for general safeguarding of reefs such as addressing climate change and limiting pollution and construction/development. Several of these are worth particular mention because they could be easily incorporated by the Cayman Islands government. Preventing the import of single use plastics, such as straws and food containers, would mean these items would not even be available for purchase in the country. Likewise, prohibiting the import of sunscreen that is not reef safe would help protect reefs. While it may not be possible to prevent use of sunscreen brought into the country, only allowing the sale of reef-safe product would be a positive step.

Education was also a clear priority for the focus group attendees. They see a need for it within schools, the government and the community in general. CCMI offers several programmes including ‘Sea Camp’ for teenagers, Reefs Go Live for schools and the monthly lecture series for the community. But there is room for expansion and CCMI could do much more with additional funding.

Finally, there is a great willingness among the population (at least the attendees of these meetings) to take pro-active steps towards improving the reef. Over half of all attendees gave email addresses or phone numbers to be contacted for follow-up. One respondent wrote, “There's an army of volunteers (like with lionfish)- harness them.”

Many people appreciate the value of coral reefs and are keen to assist in making positive change. This opens additional options for research and conservation in the Cayman Islands and should be leveraged for the preservation of the reefs.

Picture 6: Discussion with the Focus Group on Grand Cayman

Recommendations

1. Currently, the three key consumers of macroalgae in the Cayman Islands are the Bermuda chub (Kyphosus spp.), redband parrotfish (Sparisoma aurofrenatum) and blue tang (Acanthurus coeruleus). Densities of these species (from CCMI AGRRA surveys) have been constant over the past 20 years and these species are not heavily targeted by fishermen currently. This, plus the approval of the MPA enhancement plan, suggests there is no need for species-specific fishing restrictions or management policies at this time. Instead, it would be prudent to monitor these species and revaluate this strategy should their densities ever start to decline.

2. Should declines occur, one option for protection is to increase the legal-size limit from 8 inches total length to 10 inches. This would be a minor change in legislation but would be sufficient to extend protection to the blue tang and redband parrotfish.

3. The two main consumers of turf algae are the queen parrotfish (Scarus vetula) and the stoplight (Sparisoma viride). While turf algae are not currently a dominant benthic group on the north side of the three islands (Figure 2), they are prevalent on the south side (of Cayman Brac) in the summer. This should be monitored because if turf algae become a consistent presence on the reef and become as prevalent in winter as they are in summer, they will become a substantial component of the benthic community. As they are also detrimental to corals and are considered a problem group, measures will need to be taken to control them if their abundance becomes perennial.

4. Interviews with fishermen reveal that fishing is both a monetary activity as well as a cultural pastime and so, care should be taken when imposing regulations. Any regulations that are not completely necessary should be avoided. One method that could reduce fishing would be to loosen the stipulations on work permits so that ex-patriots could work additional hours (part-time) on top of their full-time contract. This would open the possibility of obtaining extra income outside work hours and thus might reduce the time available for (and the need for) fishing.

5. The Bermuda chub is highly understudied. This omission may be because measurements of Kyphosus densities may be artificially low and hence their impact may have been underappreciated. It is likely that traditional survey protocols miss many Kyphosus because of their distribution and behaviour. At least on Cayman reefs we see solitary individuals in the shallows (5 m to 8 m depth) and large schools of Kyphosus off the drop-off around 25 m to 30 m depth. Yet the AGRRA protocol for example stipulates fish transects be conducted between 1 – 5 m and 8 – 15 m (version 2.2). Similarly, survey protocols specify transects be conducted over the middle of the day (between 1000 hours and 1400 hours in the AGRRA protocol version 2.2). Yet Kyphosus are known to use specific reef areas at specific times of day (Eristhee and Oxenford 2001) so could often be missed in surveys that only occur in the middle of the day. Consequently, as ‘roving herbivores’ they may be difficult to quantify during fish surveys but could still significantly impact algal communities. Survey protocols should be designed and implemented specifically to monitor these separate species. Conducting transects parallel to shore from shore to the wall and marking where solitary and schooling individuals are found would robustly identify where these fish reside and would inform a map of their distribution. Additionally, representative sections of the reef and adjacent systems (lagoon or mangrove) should be selected on each island to be surveyed in winter and summer so changes in Kyphosus spp. abundance and distribution can be assessed.

6. Stable isotope analysis of Kyphosus diet showed that fish in some locations are not feeding as herbivores. Instead, it seems they are consuming bait (soldier crab, squid, squeezy cheese) or sewage outflow from the Turtle Centre. While at present this is a localised phenomenon, we recommend it be monitored. If herbivorous fishes show a carnivorous signal at too many sites, there could be reduced herbivory on the reef, so it may be necessary to impose restrictions on fish feeding.

7. Data indicates that Kyphosus spp. display higher site fidelity in summer than currently appreciated. However, their movements in winter are unknown. Determining their home

range and whether this varies seasonally will have an important bearing on their impact on the reef.

8. This study updates our understanding of Kyphosus spp. movements and diet. But at present we have no idea of how many species are present and their abundance and distribution. The paucity of this information extends across the Caribbean and is problematic. It is vital to learn more about them so that they can be adequately monitored and protected.

9. The responses from the focus groups highlighted the momentum that is present among the focus group attendants to learn more and act now. CCMI is in an excellent position to involve these volunteers in asking the next stage of questions and making positive change.

10. For example, we need to test manual removal of seaweed from the reef and determine how various methods impact the benthic community. Several methods could be employed but some may kill or harm other species. Similarly, algal removal in some cases has the potential to exacerbate the situation. Testing these methods and determining the most appropriate course of action for each island would enable us firstly to make clear recommendations, and secondly provide training for the dive community to get involved.

11. We must also investigate how algal removal interacts with restoration techniques. Considering that seaweed is a major stressor to corals and that we have a number of volunteers keen to improve reef conditions, we could make great strides in reducing seaweed cover and increasing coral cover in sections of the reef. How do we best employ volunteer time and effort? What methods reap the greatest reward? These are key questions for the future.

12. Following from this, Mumby et al. (2007a) modelled the increase in herbivores that would be necessary to reverse a coral-algal phase shift and reported that by increasing coral cover from 5% to 30%, twofold fewer herbivores would be required. Therefore,

efforts should be aimed and increasing coral cover in concert with conservation of herbivores and reduction of macroalgae.

13. Also in response to the focus group attendees, increased educational efforts are needed within schools, the government and the community in general. At present, CCMI offers several programmes including ‘Sea Camp’ for teenagers, Reefs Go Live for schools and the monthly lecture series for the community. Expanding these programmes would improve the understand , but there is both room for and need for expansion and CCMI could have a real positive impact with additional funding.

14. For example, CCMI education staff on each island could form a more permanent component of the school curriculum. The ability to offer more scholarships would allow more local children to attend the CCMI programmes. Broadcasting the lecture series across all islands would enable the community across the country to learn about these issues and CCMI’s work.

15. Environmental awareness among the expat population is much lower on Cayman Brac than on Grand Cayman. This is probably because CCMI is much less visible on that island than the other two. CCMI makes fewer school visits and rarely offers lectures or events on Cayman Brac so it is understandable that the community there is less informed. This should be a particular focus in future and funding to broadcast the lecture series and run activities with the schools would help remediate the situation.

Summary

The overall increase in macroalgae over the past 20 years is problematic and so the species that consume it promote reef resilience. The dominant species of macroalgae in the Cayman Islands are Dictyota spp., Lobophora variegata and Microdictyon marinum and the fish species that consume them are the Bermuda chub (Kyphosus spp.), blue tang (Acanthurus coeruleus) and redband parrotfish (Sparisoma aurofrenatum). Interestingly, Kyphosus spp. are recognised as important herbivores in the Indo-Pacific but are largely ignored here in the Caribbean. The focus in this region has been predominantly on parrotfishes, but also surgeonfishes (Duran et al. 2018). We found that at a local scale, Kyphosus spp. has an equivalent impact on macroalgal removal as the other two browsers and should be included as one of the key herbivores in the country.

Our results also determined that these species are not currently under pressure from fishing. Imposing pre-emptive species-specific restrictions is not recommended at present because this would not impact the fish populations and would only alienate/aggravate the fishing community. Coral reefs in the Cayman Islands and across the world are at serious risk. They provide multiple benefits and economic opportunities to people across the world, but most especially to those who use them daily. The population of the Cayman Islands realise this and are motivated to take action. This is an exceptional opportunity for CCMI and for the Darwin Initiative to continue this excellent work and make positive change in the environment. We have much still to learn and a tremendous amount to do if we are to safeguard coral reefs for the future, but the Cayman Islands presents a situation with a motivated workforce and active research programme/agenda. If we capitalise on this momentum, we can answer some pressing questions that will be of use to reef conservationists worldwide and could perhaps improve reefs conditions for the future.