WWF Ocean’s 10 Species Status Summary November 2007 Brain corals (e.g. Platygyra carnosus) IUCN Red List status: Not Assessed Hong Kong Status: Brain corals are assumed for this summary as suffering from the same trends as other hard reef-building corals, as most data does not distinguish between them. From 2005 to 2006, overall coral coverage remained stable (AFCD 2006), but threats remain especially outside the 3 marine parks created for them. Also the damage to one community within the Hoi Wan Marine Park suggests that allowing fishing there has resulted in an ecosystem imbalance to the detriment of the corals. Along with the Chinese white dolphin and seagrass, corals are the best protected marine species in Hong Kong. Primary protection lies in three marine parks, and some further conservation measures within Hoi Ha Wan Marine Park (two areas of corals off-limits to motorized vessels, and one to inboard vessels) and Tung Ping Chau Marine Park (two core areas around the richest coral communities where all fishing is prohibited). Also no-anchoring zones have been created in recent years by the Agriculture, Fisheries and Conservation Dept. (AFCD) around other important coral communities at Bluff, Port and Sharp Islands to reduce anchor damage which appear to have been successful. Most coral communities in eastern waters are found off the shorelines of Country Parks where development is prohibited, so development pressure should not be an issue in the short-medium term. Corals are also Species of Conservation Interest under the Environmental Impact Assessment Ordinance meaning special consideration must be given to avoiding causing harm to them. The “Coral Beach” site at Hoi Ha Wan Marine Park shows signs of ecosystem imbalance. The coral community has been closed to all visitors since May 2007 to allow restoration measures and recovery following damage and collapse of some coral heads following attacks by two invertebrate predators. The most likely explanation for the high numbers of these invertebrates is a lack of the large predatory fish that exist in Hong Kong and would otherwise feed on them. WWF research suggests that the commercial fishing that continues within the marine parks is preventing fish 1
populations from recovering within them. As part of its Save Our Seas campaign, WWF is advocating for all fishing to cease in marine parks. Threats summary
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Anchor damage
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Pollution, particularly in western waters
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Increased sediment levels, such as from reclamation, dredging and construction
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Being smothered by abandoned gill nets, known as “ghost” nets
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Outbreaks of natural predators leading to bio-erosion which can weaken resistance to storm damage etc
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Climate change and increasing temperatures will undoubtedly be a future threat
WWF Recommendations
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Continue and expand the geographic coverage of marine parks, and no anchoring zones around the richest coral communities, and continue monitoring efforts
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Stop fishing in the marine parks to eliminate physical damage from nets and traps. This would also allow fish populations to recover and probably for the ecosystem balance to also be restored through increased numbers of predatory fish (see above). This measure would, therefore, increase the effectiveness of marine parks in conserving the corals within them
•
Place all hard coral species under the Wild Animal Protection Ordinance (Cap 170) which would make harvesting or disturbance of them illegal
2
Purple Sea Urchin (Anthocidaris crassispina)
IUCN Red List Status: Not assessed Hong Kong Status: Still common in Hong Kong, but has declined Although Purple sea urchins are still common in Hong Kong, a 2006 study found a decrease in the Purple sea urchin population has occurred since the early 1980s. Purple sea urchins in south-eastern waters in Hong Kong had an average density of 6 urchins/m² in 2005 (Stark, 2006), lower than an earlier study in 1983 that recorded urchin density ranging from 5.4 individuals/m² to 22.3 urchins/m² (Chiu, 1987). Sea urchins graze hard surfaces and are important in structuring marine communities. The decline of sea urchin populations has large ecological impacts, which is shown for example in an increase in the abundance and biomass of algae (Stark, 2006). Intensive harvesting by divers to collect the roe for sashimi in Japanese restaurants puts heavy pressure on the urchin populations. Purple sea urchins which are living in Marine Reserves and Parks are the best protected, although poaching does occur. In Hong Kong, there are no restrictions on fishing Purple sea urchins outside the Marine Reserve and parks although much of the current harvesting is being done by fishers from the mainland operating illegally in Hong Kong waters. Further declines are possible. Threats summary
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Over-fishing, including illegal harvesting
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Pollution in western waters
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Loss of habitat through reclamation
WWF Recommendations
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Continued actions by Marine Police and AFCD to prevent illegal fishing from the mainland, and in Marine Reserve and Parks
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Monitoring of Purple sea urchin populations and increased management measures in future should declines continue
3
Hong Kong Grouper (Epinephelus akaara) IUCN Red List Status: Endangered (2006) Hong Kong Status: Population depleted, and no known change in recent years It is estimated that the Hong Kong grouper population in China has declined by 90%, and 50% in Japan and in the Republic of Korea (Cornish 2003). It does not occur in other countries and thus has a somewhat limited range for a grouper species. Overall, the global population of Hong Kong grouper is estimated to have declined by 63% (Cornish, 2003). The decline of the Hong Kong grouper led to it being listed as Endangered by IUCN in 2006. No additional conservation measures have been taken by AFCD to protect Hong Kong grouper since the IUCN listing. The Hong Kong grouper is one of the most popular food fishes in Hong Kong. It used to be commonly caught both as adults, and as juveniles which would be grown to market size in floating cages. Wild caught Hong Kong grouper have been scarce for at least the past 10 years. AFCD has not collected data on fishery catches in Hong Kong waters since 2002 so there is no recent update on grouper catches, or on possible population sizes. However their preferred habitat of rocky reefs continues to be intensively fished by a growing fleet of small outboard-powered fishing boats, and both adults and juveniles are rarely taken and infrequently seen in markets. AFCD places no controls on the amount of fish these vessels can take, including Hong Kong grouper. Although the species can be hatchery produced, this does not occur at commercial level and most Hong Kong grouper on sale comes from the wild, sometimes after a period of grow-out. No conservation measures exist in Hong Kong that could assist in the recovery of this once important species except for the one Marine Reserve (where fishing is prohibited) and four Marine Parks, where trawling is banned however, in these parks other kinds of commercial fishing that could harvest grouper continue under permit and involves hundreds of fisheries so these Marine Parks give little of any protection to this species. WWF research suggests that the commercial fishing that continues within the marine parks is preventing fish populations and particularly fishes like grouper from recovering within them. In the absence of new data and conservation measures, and while fishing pressure remains high, it seems unlikely there have been significant changes in 4
populations of Hong Kong grouper in recent years, other than continued declines. Most Hong Kong grouper in the markets in Hong Kong have been cultured from juveniles caught in the wild through grow-out of wild caught juveniles in China. Threats summary
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Over-fishing
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Pollution in western waters
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Loss of habitat through reclamation
WWF Recommendations
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Banning all fishing in marine parks would greatly increase their effectiveness in protecting exploited fish species including Hong Kong grouper
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Urgent introduction of sustainable fisheries management, monitoring and enforcement outside the Marine Parks and Reserve.
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Fishers should be required to report catches of this particular species and AFCD to collect the data.
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Detailed study on the current status of Hong Kong grouper
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Hatchery production of juveniles at commercial levels to take pressure of wild juveniles.
5
Chinese Bahaba (Bahaba taipingensis) IUCN Red List Status: Critically Endangered (2006) Hong Kong Status: Global population assessed as Critically Endangered in 2006 and is now extremely scarce in Hong Kong waters The Chinese Bahaba (a species of croaker) has a small global distribution, being restricted to the coast of China from the Yangtze River southwards to Hong Kong. They can reach 2m in length. In Hong Kong, they used to be found in southern waters, especially Po Toi Island, Soko Islands, and the Castle Peak region. In summer, the Chinese Bahaba used to gather in the Pearl River in large spawning aggregations, breeding in shallow estuaries. When mating was over, they migrated back to deep water. Catches are reported from the mouths of major estuaries that the species enters seasonally to spawn in large aggregations; the Yangtze River, Zhoushan Is., Min River, and the Pearl River from Hong Kong up to Taiping. In Hong Kong the Chinese Bahaba, is often referred to as “Tai O fish”, as it was commonly caught by fishermen in Tai O, Lantau (Sadovy and Cheung, 2003). Recent information on the Chinese Bahaba is limited. But there is no denying that Chinese Bahaba populations have precipitously declined and they are close to global extinction. They are fished primarily for their swimbladder, which is considered high in medicinal value and used in health tonics. The spawning aggregations are particularly vulnerable to fishing, have been intensively fished with disastrous consequences. In the 1930s, about 50 tonnes of Chinese Bahaba were caught annually. In 2000, only around 2.5 tonnes were caught. Up until 2004, less than a tonne of them were recorded and catches were small (Ng and Cheung, 2006). The price of swimbladders depends on the shape, sex and size of the fish, as well as the place and season of capture. As the maximum sustainable yield of Chinese Bahaba has decreased, the price of their swimbladders has increased. In 2000/2001, the price of the Chinese Bahaba swimbladder was between US$20,000 and US$64,000 per kg (Lin, 1939; Chu and Wu, 1985; Sadovy and Cheung, 2003). In the last couple of years, two large Chinese Bahaba caught in southern China were the subject of news articles, selling for upwards of HK$500,000 each. Chinese Bahaba are listed as a Grade II State Protected Species in mainland China, 6
and as a Protected Species in Guangdong, meaning they can’t legally be fished although still are. The Chinese Bahaba Nature Reserve was established in Dongguan in 2005 and aims to protect the spawning ground. In 2006, the Chinese Bahaba was listed for the first time as Critically Endangered on the IUCN Red List. Despite being Critically Endangered, AFCD have not taken any measures to protect the Chinese Bahaba in Hong Kong, such as placing restrictions on fishing for the species which they have the legislation to do. The Bahaba’s preferred habitat of sand and mud continues to be scoured by trawlers daily. Only the western marine park of Sha Chau and Lung Kwu Chau offers any protection but as commercial fishing using gears which could catch Chinese Bahaba continues, this protection is likely to be ineffective. Reclamation and other development pressures in western waters are also reducing or degrading habitat for the Chinese Bahaba. Threats summary
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Over-fishing
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Loss of habitat particularly through reclamation in western waters, now and in the near future
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Pollution in western waters
WWF Recommendations
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WWF calls on government to recognise that global extinction of the Chinese Bahaba is a very real possibility, and to take responsibility for urgently implementing measures to conserve the species in local waters, and in conjunction with mainland authorities.
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An immediate ban on the catching of Chinese Bahaba should be introduced and a Chinese Bahaba Conservation Action Plan formulated to restore populations.
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A seasonal closure of the spawning area to all fishing would be a likely important conservation measure within the Action Plan
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Uplisting of Chinese Bahaba to the Grade I State Protected Species in mainland China. 7
Green Turtles (Chelonia mydas) IUCN Red List Status: Endangered (2004) Hong Kong Status: The only known regularly used nesting beach has not visited in the past four years, sightings are increasingly rare and the species is well on its way to extinction in Hong Kong Green turtles exhibit particularly slow growth rates, and age to maturity for the species appears to be the longest of any sea turtle (Hirth 1997) meaning they will be very slow to recover from reductions in population size. Female green turtles usually nest once every two to five years and only one in 1000 juvenile green turtles survives to adulthood (Chan, 2003). Green turtles return to their natal beach for nesting. Sham Wan at southern Lamma Island was the last regularly used nesting beach for Green turtles in Hong Kong. Prior to this beach becoming protected and made off-limits to visitors starting in 1999 during the nesting season (June to October), nearby villagers used to dig up the eggs to eat, which probably played a big part in the turtles local demise. The last nesting at Sham Wan occurred in 2003. Other local beaches were used in the past by green turtles but have become abandoned as housing and particularly bright lights have spread to most beaches. Odd nestings still occur very rarely, for instance one female at Tai Long Wan in Sai Kung in 2006, and another at Big Wave Bay near Shek O in 2005, but these last survivors will not be able to maintain a Hong Kong population. Females lay several hundred eggs but as the survival rate is only around 1 in a thousand, numbers are against the turtles. Even if a few individuals from the 1990s generation of nestlings or earlier return to Lamma in the future, it seems unlikely they can produce enough eggs to perpetuate the Hong Kong population. Green turtles are highly migratory, and therefore may require protection throughout their migratory route in order for conservation to be effective. Green turtles satellite-tagged by AFCD in Hong Kong have traveled to Hainan Island where an illegal trade exists in dead turtles as curios. For example, in March 2007 a Chinese vessel from Hainan was caught in Malaysia with more than 220 Green and Hawksbill turtles illegally on board (WWF HK, 2007). 8
Threats summary
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Harvesting of eggs from nesting beaches in Hong Kong in the past
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Disturbance of nesting beaches in the past and now
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Bycatch in trawl nets, and possibly gill nets when young
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Health problems caused by swallowing plastic bags and other physical rubbish
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Boat collisions leading to injury or mortality
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Outside Hong Kong - threats not well known but including being caught for meat and curio trade, and being caught as bycatch
WWF Recommendations
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AFCD has taken solid conservation actions in restricting human access to the nesting beach at Sham Wan on Lamma Island during the nesting season since 1999, and in successfully removing laid eggs, incubating them (with partner Ocean Park) and releasing the juveniles in order to increase their early survival rate. However, all the available information suggests these actions by themselves have been too late and too limited to ensure the survival of the Green Turtle in Hong Kong.
•
WWF calls on government to recognize the desperate plight of the Green Turtle in Hong Kong and formulate a Green Turtle Conservation Action Plan to examine the feasibility of restoring viable breeding populations of the species in Hong Kong.
9
Yellow Croaker (Larimichthys polyactis) IUCN Red List Status: Not Assessed Hong Kong Status: Population depleted, and no known change in recent years The Yellow croaker is one of the most popular food fishes in Hong Kong, and used to be seasonally common in western waters, but wild caught croaker have been uncommon since the 1970s (Min pers. comm.). AFCD has not collected data on fishery catches in Hong Kong waters since 2002 so there is no update on yellow croaker catches (and possible changes in population size). However, their preferred habitat of sand and mud continues to be scoured by trawlers daily and no conservation measures exist except for the four Marine Parks, where trawling is banned but other kinds of commercial fishing that could harvest croaker continue under permit. AFCD places no controls on the amount of fish including Yellow croaker that can be taken within or outside the Marine Parks. In the absence of new data and conservation measures, and while fishing pressure remains high, it seems unlikely there have been significant changes in the status of Yellow croaker. In the late 1930s, Yellow croaker were abundant in Hong Kong waters from September to December when they gathered in big schools in western waters such as around Cheung Chau, and Lantau Island. At this time the schools were so large and profitable to target that the shrimp trawlers stopped fishing for shrimp and joined other boats using a special kind of gill net to target the Yellow croaker.
The “drumming” noise the
fish made was so loud that fishermen could locate the schools by placing an ear against the hull of their boats (Lin 1940; Chu 1960). Although the species was once supported an important dedicated seasonal fishery, these schools have not formed in Hong Kong since the 1980s (Min pers. comm.). Pollution, reclamation, dredging and dumping have also played a part in reducing the quality of habitat in western waters for Yellow croaker. Most Yellow croaker in the markets in Hong Kong today have been farmed in China from juveniles that have been raised in hatcheries and restocking initiatives within China have produced no discernible recoveries in the species.
10
Threats summary
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Over-fishing
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Pollution in western waters
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Loss of habitat particularly through reclamation in western waters
WWF Recommendations
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Banning all fishing in the western Sha Chau and Lung Kwu Chau Marine Park would greatly increase its effectiveness in protecting exploited fish species
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Urgent introduction of sustainable fisheries management, monitoring and enforcement outside the Marine Parks and Reserve
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Fishers should be required to report catches of this particular species and AFCD required to collect such data.
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A seasonal closure of the spawning area to all fishing to protect the species
11
Japanese Eelgrass (Zostera japonica) IUCN Red List Status: Not Assessed Hong Kong Status: Apparently stable but remaining vulnerable Hong Kong appears to be a less than ideal locality for seagrass as they occur only patchily and even the largest beds are relatively small. Japanese Eelgrass is one of the more common species but is taken to be representative of all the seagrass species known in Hong Kong as they suffer from similar pressures and some species occur in mixed species seagrass beds. Seagrass is vulnerable to pollution and increased sediment levels, and probably therefore most under threat in western waters where development pressures and pollution from the Pearl River Delta remain high. Seagrass is better protected in eastern waters, notably in the Yan Chau Tong/Li Chi Wo Marine Park. The largest area of Z. japonica in Hong Kong at about 10,700 m2 is found there. New seagrass beds have been discovered in recent years and a new species to Hong Kong, Halophila minor was found in To Kwa Peng in 2005 (Kwok et al, 2005a). Lai Chi Wo and San Tau have been designated as “Site of Special Scientific Interest” (SSSI) and Sheung Sze Wan has already been designated as “Coastal Protection Area”. Seagrass beds are considered to be important habitats under the Environmental Impact Assessment Ordinance (Kwok et al, 2005b).
Threats summary •
Pollution
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Increased sediment levels, such as from reclamation, dredging and construction
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Pesticide run-off from land
WWF Recommendations
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Continued monitoring of seagrass beds and increased management measures in future should declines occur
12
Horseshoe Crabs (Carcinoscorpius rotundicauda) IUCN Red List Status: Data Deficient (1994) Hong Kong Status: In serious decline Horseshoe crabs have suffered alarming drops in numbers in recent decades. 25 years ago, horseshoe crabs were numerous in Hong Kong. They used to spawn at Cheung Chau, Tai Tam, and even inside Tolo Harbour.
The population of horseshoe
crab in Hong Kong has seriously declined. On average in each 1000 m2 of Hong Kong’s shoreline and coastal waters, only one or two horseshoe crabs were found in 2004. Compared with the figure in 2001, the number of crabs has dropped 90% (Lai, 2007). Also, in the 1980s and 1990s, three Horseshoe crab species existed in Hong Kong, but recent surveys have found just two, and one of these in very low numbers. One likely reason is that Horseshoe crabs are continually being fished. Although this happened in the past, they were often released as they have relatively little meat, and fetched a low price. However, as other more desirable species have declined in numbers, fishers now keep and sell previously undesirable species to sustain income – known as fishing down the food web. A market survey conducted from Sept 04 to Sept 05, found around 50 horseshoe crabs are sold to seafood markets and restaurants every month, with about half coming from Hong Kong waters (Shin et al., 2007). Although most of the Horseshoe crabs are caught and kept for display only, without proper care, they will eventually die and be replaced by more from the wild. The major problem though is the development and pollution of the shoreline where the Horseshoe crabs lay their eggs and spend their early years. Females lay up to 2,000 eggs on the high tide in spring but even with optimal conditions only one or two per 10,000 survive to sexual maturity. If development continues as at present, and the spawning and nursery areas are lost, the Horseshoe crab’s days are numbered in Hong Kong. Horseshoe crabs take a long time – 10-15 years – to reach sexual maturity, so that they will take a long time to recover from declines. There are no restrictions on catching horseshoe crabs in Hong Kong, nor other specific conservation measures.
13
Threats summary
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Loss of habitat, through reclamation and other shoreline development
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Over-fishing
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Pollution, particularly in western waters
WWF Recommendations
•
WWF calls on government to recognize that both remaining species of Horseshoe crabs are in serious trouble in Hong Kong and proactively formulate and implement a Horseshoe Crab Conservation Action Plan now, rather than waiting until the situation deteriorates further, whereupon conservation will be even more difficult. An obvious measure would be to prohibit the catching and selling of any Horseshoe crab in Hong Kong
•
Important nursery shores such as Shui Hau Wan and San Tau should be designated as Site of Special Scientific Interest (SSSI) or Special Conservation Area (CA) to prevent further developments in these important habitats
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The public should stop eating Horseshoe crabs while they are still sold, and thus reduce fishing pressure on them.
14
Chinese White Dolphin (Sousa chinensis) IUCN Red List Status: Data Deficient (1994) Hong Kong Status – Stable but threats are serious and mounting According to the latest information released by the Agriculture, Fisheries and Conservation Department (AFCD), 1,300-1,500 dolphins occur in Hong Kong and adjacent Pearl River Estuary waters (AFCD, 2007a). As yet, a total population size has not been estimated for the greater Pearl River Estuary. The number of individual dolphins which occur in Hong Kong’s waters ranges from approximately 207 in autumn to approximately 91 in spring (Jefferson et al. 2005). The AFCD led-stranding programme has recorded a total of 105 dead Chinese white dolphin (CWD) in the last 10 years. (AFCD, 2006; OPCFHK, 2007). The cause of death for most of these individuals is largely unknown, although entanglement with fishing gear, injury from vessels and high pollution levels have been responsible for several deaths. The majority of deaths are of young or newborn dolphins. The dolphin population is under considerable stress due to habitat loss and degradation, pollution, reduction in food availability, increases in vessel traffic and noise pollution and disturbance from new developments, e.g., dredging and dumping. Although the size of the Pearl River Estuary CWD population has remained relatively stable at a minimum of 1300 individuals in the last 10 years, detailed long-term population trends are not well understood, and the mortality of young dolphins remains a concern. Without a large and healthy younger generation, the long-term survival of the population is in doubt. AFCD has a CWD conservation programme and action plan, but little real progress has been made in implementing the conservation measures identified since the plan was formulated in 2000. The Sha Chau and Lung Kwu Chau Marine Park, the so called ‘dolphin sanctuary’ should be a key component of this conservation plan but its effectiveness may be limited as it does not remove those threats which directly cause mortality. Even within the Marine Park area, development and habitat modification is allowed.
The Marine Park should also provide increased feeding opportunities for
CWD by allowing fish and other food stocks to increase. However, commercial fishing 15
under permit is still allowed within the Marine Park and the dolphins still compete with fishing for food. Threats summary
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Pollution in western waters
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Loss of habitat, through reclamation and other shoreline and seabed development
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Over-fishing of the main species the CWD rely on
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Increased vessel traffic in western waters, doubling from 1999 to 2007
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Increased noise and other disturbances, from vessel traffic and marine construction
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Accumulation of pollutants such as heavy metals taken up from prey
WWF Recommendations
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Continuation of government funded CWD monitoring programme to carefully document changes in population and pressure from threats
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Change in government conservation efforts from a reactive, to a proactive approach whereby recommendations in the “Conservation Programme for the Chinese White Dolphin” be implemented with urgency
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Designation of an additional marine park in Western Lantau waters where CWD are now most commonly sighted (AFCD 2007b)
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Increased co-operation between Hong Kong and mainland authorities to conserve the CWD throughout the Pearl River Estuary
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An international review by cetacean experts of the effectiveness of the last 10 years of dolphin conservation and management procedures in Hong Kong
•
Development of an updated CWD Conservation Action Plan
which
encompasses management measures for the entire Pearl River Estuary and includes collaboration with adjacent authorities
16
Mudskipper (Boleophthalmus pectinirostris) IUCN Red List Status: Not Assessed Hong Kong status – Population in Deep Bay declined in the 1990s and has not fully recovered Mudskippers abound in open intertidal flats and mangroves, such as around Mai Po and Sha Tau Kok. Information on mudskipper status throughout Hong Kong is not available, so this report concentrates on Deep Bay where there is data. In the early 1990s, there used to be three species of mudskippers on the Deep Bay mudflats at a density of around 15 mudskippers per square metre of the Deep Bay mudflats. However, due to the increasing pollution in Deep Bay, and in particular a severe pollution event in 1996 which resulted in mass mortality to many organisms over a period of 2 weeks, the number of mudskippers species has dropped to two and their density has declined to around six mudskippers per square metre (WWF unpub. data). The rapid growth of Shenzhen has undoubtedly contributed to increasing pollution levels. Illegal fishing using small traps on the mudflat continues, particularly in spring when the mudskippers are mating. This harvesting in combination with the ongoing pollution are the most likely reasons why the mudskipper population has not recovered to early 1990s levels. Threats summary
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Pollution in western waters
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Loss of habitat, through reclamation and other shoreline development
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Illegal fishing in Deep Bay
WWF Recommendations
•
Stricter enforcement to prevent illegal fishing
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Greater efforts by both mainland and Hong Kong authorities to reduce pollution into Deep Bay 17
•
Introduction of sustainable fisheries management, monitoring and enforcement outside the Mai Po Nature Reserve
18
