New species of wrasse discovered in Hong Kong waters
by Andy Cornish
A new species of wrasse, Xyrichtys trivittatus has recently been described by Dr J. E. Randall of the Bishop Museum, Honolulu, and myself from a specimen caught off Lamma Island. The fish, a 12 cm male, was obtained from small-scale local fishers in October 1996 who caught it in Ha Mei Wan, the large bay to the west of Lamma Island. I photographed the fish but was puzzled as the colouration was similar to a specimen of Xyrichtys pavo pictured in “Fishes of Taiwan” (Shen et al. 1993) but differed from the written description. Dr Randall, a mine of information on Indo-Pacific, fishes visited Hong Kong in June 1998 and was able to confirm that the Lamma specimen was an undescribed species. The specimen photographed in the “Fishes of Taiwan” was located and proved to be the same, and so we described X. trivittatus with the Hong Kong specimen as the holotype and the Taiwanese individual as the paratype. We have given this fish the common name Triple Barred Razorfish. Colouration is primarily yellowish-grey with three vertical black bars on the upper of the body and dorsal, anal and upper caudal fringed with red . There are 24 known species of Xyrichtys wrasse (including X. trivittatus) globally and only X. aneitensis (which is not known from China) also has three black bars, but in that species the bars end in spots dorsally.
In an attempt to gain more specimens of the Triple Barred Razorfish I circulated a picture of the first specimen and a wanted notice offering $100 a specimen to the fishers in Yung Shue Wan, Lamma. This eventually proved fruitful with another two specimens turning up from west Lamma in summer 1999. Dr Randall also located some preserved specimens that had been collected in Vietnam. Razorfishes inhabit open areas of sand which they dive under when threatened. The catch locations and the fact that a species with such distinct colouration had not been previously been noted from Hong Kong suggest that the species is scarce locally and inhabits shallow areas of clean sand between the coast and the highly disturbed trawl grounds. The challenge now is to photograph this species in its natural habitat.
Randall J.E. & A.S. Cornish. (2000). Xyrichtys trivittatus, a new species of razorfish (Perciformes: Labridae) from Hong Kong and Taiwan. Zoological Studies 39(1): 18-21
Sadovy Y. & A.S. Cornish. (2000). Reef fishes of Hong Kong. Hong Kong University Press. pp 321.
Shen S. C., C. H. Chen, C. T. Chen, S. C. Lee, H. K. Mok & K. T. Shao. (1993). Fishes of Taiwan. University of Taiwan, Dept. of Zoology. In Chinese. pp 960.
Hot off the press is the “Reef Fishes of Hong Kong”. This book includes descriptions and colour photographs (including one of this new wrasse species) of over 320 species from 70 families. A third of these records are new to Hong Kong and there is at least one species new to science (the wrasse). In compiling information for this book it became clear that species once common are now rare and that local reef fishes face serious impacts from coastal activities, the most serious of which is, without doubt, overfishing. Get your copy now, while stocks last!
Fish stocks bounce back at Cape d’Aguilar
by Andy Cornish
Numbers of large reef fishes have shown a dramatic increase within the Cape d’Aguilar Marine Reserve this summer. Fishing was banned in the Reserve in July 1996. Semi-quantitative records show that smaller fishes, e.g. damselfish, increased in number in the first few years of protection while larger food fishes such as Painted sweetlips, Diagramma pictum and Mangrove red snapper, Lutjanus argentimaculatus, increased in size and number far more slowly.
Recent dives on 15 and 16 June to exposed rocky reef at around 10 m revealed a huge increase in abundance, diversity and size of larger reef fish to anything seen previously. Species present with individuals greater than 30 cm total length included Smallspotted dart, Trachinotus bailloni, Longtooth grouper, Epinephelus bruneus, Leopard coral-grouper, Plectropomus leopardus, John’s snapper, Lutjanus johnii, Star snapper, Lutjanus stellatus, Picnic seabream, Acanthopagrus berda, Surf bream, Acanthopagrus cf. australis, Red pargo, Pagrus major, Harry hotlips, Plectorhinchus gibbosus, Spangled emperor, Lethrinus nebulosus, Spottedtail morwong, Cheilodactylus zonatus, Spotted nibbler, Girella punctata, Blue sea-chubb, Kyphosus cinerascens, Blue-barred parrotfish, Scarus ghobban, Knobsnout parrotfish, Scarus ovifrons, Pickhandle barracuda, Sphyraena jello, Scalpel sawtail, Prionurus scalprus, as well as the Mangove red snapper and Painted sweetlips. Some of these fishes, such as Knobsnout parrotfish and Longtooth grouper are rarely seen nowadays in local waters, indeed on many dives in Hong Kong no fish larger than 30 cm are encountered. Other rarities included Longface emperor, Lethrinus olivaceus, a new record for Hong Kong, Barred knifejaw, Oplegnathus fasciatus, a small school of Little tuna, Euthynnus affinis, and around twenty Dory snapper, Lutjanus fulviflamma, a secretive fish that I have only recorded singly before.
The increase in larger fishes seems to be due to cessation of fishing, allowing resident fish to grow without being caught, and immigration into the reserve. Immigration is likely for fishes such as a school of fifteen Pickhandle barracuda of 90 cm length which had not previously been seen in the 18 ha. reserve. Such carnivorous fish may be attracted by large numbers of small, potential prey species.
Remarkably, almost all of the larger fishes were untroubled by divers and could be approached to within a few metres. All of the named fishes are targets for spearfishers and are generally very wary of divers in Hong Kong. It seems that fish within the reserve have slowly become acclimatized to visits by divers who do not harass or shoot them (diving within the reserve requires a permit from Agriculture, Fisheries and Conservation Department). Even two 70 cm length Knobsnout parrotfishfish, which have not been encountered in the reserve previously, were quite bold, perhaps picking up on the untrouuntroubled reaction of other fish to divers. The dramatic change in behaviour in just four years within a protected area is great news for divers who currently have little chance of diving with large fish on natural reefs in Hong Kong. It does make the fish increasingly vulnerable to poaching by spearfishers, however, a problem already faced by the Clearwater Bay Marina where fishing is also banned.
by Yvonne Sadovy
Recently, several species of non-native fishes have been sighted or captured in Hong Kong’s marine waters. Divers have variously reported a single observation of a rather battered looking tiger grouper, Epinephelus fuscoguttatus, a species not known to occur along the continental land mass, and a number of red drum, Sciaenops ocellatus, a species from the western Atlantic (FishBase, 1998). The red drum has also been taken by recreational fishermen, both from around Ma Wan and off Sai Kung. Both species probably escaped from mariculture zones. Although the tiger grouper is not cultured as such, it is often held briefly in floating net cages near shore prior to sale. The red drum, on the other hand, is imported as fingerlings (several inches long) for grow-out. This species typically inhabits sand and muddy bottoms in coastal and estuarine areas and, based on the numbers being reported, survives around Hong Kong. It is not known whether it is reproducing locally.
The successful establishment of introduced marine fishes is less common than for freshwater species but is nonetheless reason for concern. The best known example is 27 introductions (21 for food and 6 others) into Hawaiian waters. Thirteen of these species became established, several with unfortunate consequences; two are known to cause human poisoning (ciguatera), while several had no food value for humans (Bohnsack, 1996), or outcompeted closely related native species. Even among those suitable for human consumption,many were not readily accepted by the public.
The history of freshwater fish introductions both in Hong Kong and elsewhere includes many examples where newly established species have evidently displaced or outcompeted local species with negative impact on fisheries. Several introduced freshwater species found in Hong Kong streams, for example, have become established. Live-bearers from central America (poeciliids) were brought in to control the larvae of mosquitoes, or were released by aquarists and may have negatively affected native species (Dudgeon and Corlett, 1994). In a clear warning over the problems of introductions for fishery purposes, W. L. Chan (Government Fisheries Research Division) wrote in 1976: “The introduction of the mouthbrooder, Tilapia,” (Oreochromis mossambicus) “is perhaps the biggest mistake ever made by fish culturists. Initially, this species was introduced to a brackish water fish farm for culture trial, but has subsequently found its way to inland fishponds and streams. The fact that it is capable of multiplying rapidly and thrives under nearly all unfavourable environmental conditions, makes it more of a pest than a truly acceptable species from the view of both the fish culturist and the biologist” (Chan, 1976).
Currently Hong Kong has no legislation to control the introduction of alien species into local aquatic environments. Given the problems, already documented globally, created by many introductions, inadvertent or otherwise, into marine and freshwaters, and given the growing interest in restocking and mariculture as proposed solutions to the poor state of local fisheries, there is clearly need for regulation. Escapes of non-native species brought in for mariculture, transmission of disease by international trade and interbreeding of non-native genotypes with local wild populations have already created problems, here and in other areas. Disease outbreaks in our local mariculture industry in recent years have been attributed to fingerlings imported from elsewhere in the region combined with the lack of quarantine requirements. The interbreeding of native wild salmonids in Norway with escaped cultured hybrids has evidently produced individuals of lowered reproductive potential in the wild with unknown long-term consequences for the persistence of affected populations.
The consensus on introductions is that extreme caution is essential if introduction of non-native species or non-local genotypes of native species is being contemplated. We have been warned!
Bohnsack, J. A. (1996). Maintenance and recovery of reef fishery productivity. Pp. 283- 313 In: Reef Fisheries (eds. N. V. C. Polunin and C. M. Roberts). Chapman and Hall Fish and Fisheries Series 20.
Chan, W. L. (1976). The fish fauna of Hong Kong. Pp. 108-127 In: The fauna of Hong Kong (ed. B. Lofts). The Hong Kong Branch of the Royal Asiatic Society.
Dudgeon, D. and R. Corlett. (1994). Hills and streams. Hong Kong University Press.
FishBase, (1998). FishBase 1998 CD-ROM. ICLARM, Manila.
Note of interest - Barking Deer
(or muntjac) identity remains unsolved...
by Bosco Chan
I came across this brief report in the old but very interesting AFD journal Wildlife Conservation (1974):
A gentleman named Colin Gimson reported seeing an “unusually large” Barking Deer on Shek O Road, Hong Kong Island, in the evening of 14 July 1974. The deer was said to be 60 cm tall and was “not the usual light colour (of a Barking Deer) but a darker colour”.
This sighting may be of an escaped deer representing a non-native species as the author suggested, but it also fits the general description of the Indian Muntjac (Muntiacus muntjak) (e.g. Roberts, 1997). Readers are reminded that the preliminary measurements of a Barking Deer recently found in Central New Territories has been suggested as the Indian Muntjac (Muntiacus muntjak) (Reels and Crow, 1999). There are, however, many interesting reports (and photographs) of smaller, lighter colour adult deer in the series of Wildlife Conservation and Hong Kong Naturalist, which fit the description of the Chinese Muntjac (Muntiacus reevesi) ü the only species of deer we all uncritically believed is running around on our hillsides.
It is surprising that the identity of our native deer has remained uncertain (or unchecked) for so long, despite all these years of scientific research and professional management of our countryside. So do we only have the Chinese Barking Deer? The Indian Barking Deer? Chinese on Hong Kong Island and Indian on the mainland? Chinese AND Indian on Hong Kong Island (after reading Gimson’s sighting) but only Indian on the mainland, or vice versa? Or both occur all over Hong Kong? What about those living on the smaller islands? Or whatever combinations? Someone should look into this problem seriouslyüRichard, do Barking Deer disperse seeds??
Wildlife Conservation. (1974). Sightings on Wildlife. Wildlife Conservation 22/23:11
Reels, G. and Crow, P. (1999). Hong Kong’s Barking Deer ü What is it? Porcupine! 19:21.
Roberts, T. J. (1997). The Mammals of Pakistan. Oxford: Oxford University Press.
Vultures in the park (or nine days in Brazil)
by Richard Corlett
The obvious (to me!) attractions of the 5-day 3rd International Conference on Frugivores and Seed Dispersal were almost equally counterbalanced by the unpleasant prospect of at least 30 hours air travel in each direction to Southeast Brazil. What decided me in the end was the fact that the São Paulo region, where it was being held, is remarkably similar in both environment and history to the Hong Kong region. At 23°S it has a similar temperature seasonality to Hong Kong and, although the rainfall is generally lower, most of the region was once covered in semi-deciduous forest. São Paulo city was founded by the Spanish in 1554 and the succeeding centuries have seen almost total deforestation, leaving a highly degraded landscape, similar in many ways to ours, but with an independently-evolved biota. The conference itself, as it turned out, was well worth the trip (in August, 2000), but this report is confined to my extracurricular activities at the rural conference site, from dawn to breakfast every day, and on two free days in the vast city of São Paulo (population >20 million!) at the end.
Bird-wise, the trip started badly. There was no suitable field guide available in Hong Kong and the first two species I saw, at São Paulo airport, were the cosmopolitan House Sparrow and Feral Pigeon. Things started looking up when we reached the conference site at São Pedro, 200 km inland, where the hotel gardens and surrounding secondary scrub were full of weird and wonderful bird songs. Moreover, there were several enthusiastic and knowledgeable local postgrads, willing to go birding at any time of the day or night, and two bird books were available for sale. The first of these, Todas as Aves do Brasil (All the Birds of Brazil), has poor illustrations, illegible range maps, and descriptions in Portuguese, but was useful as an illustrated checklist. The other, Aves no Campus (Birds of the Campus of a University in São Paulo city) has much better illustrations of most of the common species I saw. With the initial help of the Brazilian postgrads, these books and my Leica 8 X 32 binoculars, I managed to identify most species I got a good view of, but many cryptic or highly active species were no doubt missed.
A distinctive feature of the South American bird fauna is that, although it is amazingly species-rich, there are relatively few families, each of which is huge. An apparent consequence of this, is that all the major families have radiated into most major niches, and it is often easier to recognize species than the families to which they belong. I was most interested in the frugivores, so I will start with these.
Overall, the tanagers were the most abundant frugivores, with the blue-grey, bulbul-sized Sayaca Tanager the commonest tanager at both the conference site and in urban parks in São Paulo. The five other tanager species I was able to identify were more colourful but much less abundant. The tanagers share the open-country insectivore-frugivore niche with two other major groups, the tyrant flycatchers and the thrushes. Among the 6-7 very varied tyrants I saw, the largest and most conspicuous was the Great Kiskadee, with its loud calls ("kis-ka-dee!") and bright yellow underparts. Like other tyrants, the starling-sized Kiskadee takes both fruit and insects while hovering: indeed, I saw one take insects from the water surface in a São Paulo park lake.
In striking contrast to the novelty of the rest of the bird fauna, I was surprised by the abundance and diversity of thrushes in the same genus - Turdus - as most of the species we see in Hong Kong. However, these thrushes are residents in the São Paulo region, while ours are all winter visitors. I saw four species but the only one I got a really good view of was the Rufous-bellied Thrush, which was the commonest ground bird under trees in São Paulo parks, occupying the same niche as the similar American Robin and Eurasian Blackbird elsewhere.
Among the ground-feeding granivores, the House Sparrow - introduced a century ago - was confined to areas near buildings. The commonest native "sparrow" was the Rufous-collared Sparrow, which is a member of the huge Neotropical radiation of nine-primaried oscines, which includes the tanagers and icterids (New World blackbirds and orioles). This shared bare ground and short grass with two common columbids, the tiny Ruddy Ground Dove and the much larger Picazuro Pigeon. Off the ground, the dominant seed predators are parrots. I saw flocks of the tiny Blue-winged Parrotlet feeding on the fruits of both Cecropia and figs. Although I cannot confirm this from my own observations, the literature suggests they destroy the tiny seeds of both. Noisy flocks of the larger Plain Parakeet were common in urban São Paulo.
The most abundant nectarivore (or, at least, partial nectarivore) was another nine-primaried oscine, the ubiquitous Bananaquit. There seemed to one in every tree, even in the busiest streets of São Paulo. The constant insect-like buzz in the background is largely from these birds and one ceases to notice it after a few days. However, I never stopped noticing the wonderful hummingbirds, which seemed to prefer the widely-planted Asian Bauhinia variegata over any native plant species. They don't stay still long enough for easy identification but the commonest was probably the tiny Sapphire-spangled Emerald, while the most spectacular I saw was the much larger Swallow-tailed Hummingbird.
Foliage-gleaning insectivores tend to be little brown birds everywhere, and the commonest one I could confidently identify was the ubiquitous House Wren, for which the key character given in Birds of South America is "without obvious features", which is both accurate and helpful. I also saw two species of woodpeckers in the hotel grounds, the large Campo Flicker and the tiny White-barred Piculet. The aerial insectivore niche in both rural and urban areas was dominated by the Blue-and-white Swallow, although there were probably also other species. At the other end of the size scale, Black Vultures were always visible in the sky and often perched on trees, even in the beautiful Ibirapuera Park (see side bar) in downtown São Paulo. Are they waiting for the joggers to collapse or do they feed on discarded food scraps? This park also had both Great and Snowy Egrets, and large numbers of Neotropical Cormorants. Flocks of the familiar Cattle Egret - a recent arrival in South America - flew over the hotel early every morning. Other carnivores included several species of hawks and falcons, of which I could positively identify only the roadside White-tailed Kite, and the Yellow-headed Caracaca, a species which is reputed to eat a considerable amount of fruit.
This still leaves a lot of interesting birds about which I know too little to slot them into one of the above categories. My favourite was the Rufous Hornero, a brown, thrush-like ground-feeder, which belongs, like the tyrants, to the vast New World suboscine passerine radiation. It was particularly common in Ibirapuera Park.(see side bar). I must have also seen its conspicuous mud nests, but probably mistook them for those of ants or termites, judging by the descriptions I have subsequently read. It is apparently the national bird of Argentina, which seems a rather odd choice. The Chalk-browed Mockingbird was also common in the same park, and is presumably an insectivore-frugivore. The only icterid I identified was the Shiny Cowbird, which was common in all open habitats I visited. I am not sure what this bird eats ü my books say "seeds and insects" ü but the main feature of ecological interest is that it is a brood parasite, like our cuckoos.
In contrast to the 50 or so bird species on my Brazil list, I only saw two mammal species, although both were of considerable interest. On my second dawn birdwatch, I got a very close view of a cat-sized mother and smaller baby South American Opossum. To someone familiar with only Australian marsupials, this is a weird-looking animal, but it is common and successful in almost all habitat types in South America. The other mammal was the only bat caught during a couple of hours early-evening mist-netting. Fortunately for me, this was the Short-tailed Leaf-nosed Bat, Carollia perspicillata, the best-studied open-country fruit bat of the Neotropics. I had always assumed that this species, although in a different suborder, was similar to our common Asian Cynopterus fruit bats, and was surprised to find it looks very different and is much smaller.
Birds eating figs in Brazil
by Richard Corlett
While exploring the 158 hectare Ibirapuera Park in the vast city of São Paulo, Southeast Brazil, on my way back from a conference, I came across two adjacent plants of the Asian fig species, Ficus microcarpa, which is common in Hong Kong, bearing ripe figs. I watched them for almost an hour on a cool winter morning (c. 14°C) and recorded the following seven species of birds consuming the figs. The most abundant was the Rufous-bellied Thrush, Turdus rufiventris, followed by the Sayaca Tanager, Thraupis sayaca. The Cream-bellied Thrush, T. amaurochalinus, Fawn-breasted Tanager, Pipraeidea melanonota, Burnished-buff Tanager, Tanager cayana, and Blue-winged Parrotlet, Forpus xanthopterygius, were also represented by multiple individuals, while a single Great Kiskadee, Pitangus sulphuratus, took figs from the outer part of the canopy while hovering. Longer observations would undoubtedly have added to this list, since there were other frugivorous species present in the park. All the species seen, except the parrotlet, which is a known seed predator, are likely to disperse at least some fig seeds. However, the thrushes and kiskadee, which swallowed figs whole, may be better dispersal agents than the tanagers, which apparently mashed the figs in their beaks and may not have swallowed all the seeds.
Bats observed in semi-hibernation in a mine-shaft in Macao, South China
by Emmett R. Easton
In the Choec-van area of Coloane island in Macao severalä species of bats normally reside in a horizontal tunnel approximently 55 meters in length that exits in a ravine near a stream. Fresh water flows out of the entrance of the tunnel which probably discourages entry by man and water is present over a distance of 25 meters, while the rear of the tunnel has a dry floor for a length of 30 meters and is used by 5 species of roosting bats.
During the period from March 31-April 9, 1988, when night time temperatures on the island ranged from 19-23°C, eleven great roundleaf bats, 3 least horseshoe and 5 lesser bent-winged bats were examined and released during a serological survey to determine if the mammals were carrying pathogenic agents that could be potentially dangerous to man. Blood samples were found to be negative when tested by Public health experts from the Communicable Disease Centre in Colorado of the USA.
In the spring and early summer, small numbers of common bent-winged bats as well as the great roundleaf bat have been routinely observed at this site, along with a pair of nesting violet-whistling thrushes. When the tunnel was entered on January 1, 2000, when night time temperatures were ranging from 8-13°C in Macao, the author observed approximately 120 great roundleaf bats in a semi-hibernative state hanging from the ceiling in the rear portion (last 30m) of the tunnel. Normally during the spring these bats would all exit from the site upon entry by man but on this occasion no flight activity was observed. This may be the main site from December-March for overwintering or semihibernating great roundleaf bats. Smaller numbers of common bent-winged and lesser bent-winged bats are also found in the cavern but the main maternity cave for the bent-winged bats is at Hac-sa near the Macao golf and country club in a natural cavity that emerges at the base of a sea cliff.