Fish conservation

The sustainable use of marine ecosystems, including fisheries, aquaculture,

and recreation, requires the conservation of inshore marine fish.

If we are to avoid the conservation crisis affecting many terrestrial vertebrates, marine conservation organisations, marine naturalists, scientists, and government, need to establish a sound knowledge of the species they are attempting to conserve. Within this knowledge informed and sound conservation measures can be taken.

Field work by the community and scientists to identify close inshore species, their range, distribution, habitat, and population dynamics will provide the knowledge for immediate conservation measures. At selected inshore locations the establishment of baseline populations and their long-term monitoring to detect changes in species abundance and composition are essential.

The monitoring of some vulnerable species' core populations will also be required. Diving surveys should be undertaken to reveal the range and distribution of the little known reef and rubble species.

Conservation measures for marine species should be taken within the framework of a sound knowledge of conservation needs. Such knowledge can only be gained through continuing work by both marine naturalists and scientists. For instance some species of Syngnathids that have been previously considered as endangered are probably widespread and secure, and other novel species that inhabit inshore habitats subject to development have not been recognized.

The conservation of inshore fish has traditionally received little attention in the conservation movement. However, the sustainable use of marine ecosystems, including fisheries, aquaculture, and recreation, requires the conservation of inshore marine fish. Unfortunately, damage to marine habitats or their loss has accelerated and the number of threatening processes increased. In the tropics the loss of inshore reef and estuarine habitat, threatens fish in regions of high biodiversity. In temperate areas some species are also under threat.

Many inshore fish appear are resident species and have patterns of reproduction including eggs clutches with few eggs. These and other characteristics make them vulnerable to over collecting for aquariums, habitat change, exotic predators, competitors, or disease.

Over collecting can be addressed by catch restrictions and by aquaculture to replace the collection of wild fish. Aquaculture of inshore fish for aquariums also delivers other advantages to conservation. Often aquaculture enterprises have public tours and displays with educational themes about the conservation of species and their needs. The keeping of species in aquariums will further educate and enlighten the public of the value of these species. Aquaculture also supplies the majority of syngnathids to Public Aquariums where large scale conservation programs are supported. These activities all contribute to the sustainable management of inshore fish.

In Southern Australasia there are no Syngnathid fisheries and threats to Syngnathids have largely been attributed to trawl by-catch. The conservation of Southern Australasian inshore fish is also supported by the establishment of marine reserves. There is a worldwide movement toward establishing a system of marine refuges, and in Southern Australasia, marine reserve systems in South Australia are pioneering this movement. Nevertheless, these marine reserves will be of limited value unless threats, besides fishing and the loss of the habitat in marine reserves , are clearly identified and removed. These threats can be devastating and disease, and exotic predators and competitors are a major problem of the conservation of amphibians, mammals, and birds, even in conservation parks.

For instance the successful production of Syngnathids through captive breeding reduces and will eventually eliminate the use of wild stocks. The importance for conservation of pioneering hobbyists in developing techniques for animal care and husbandry is also often overlooked. Unless animals can be successfully kept satisfactory observational and reproduction studies cannot be completed. With many Syngnathids these studies are the only means of developing the knowledge needed with further conservation needs as they develop. The significance to conservation of the recent and future pioneers that have devoted their resources, talents, and time to the development of captive rearing techniques should not be underestimated.

Of the many different types of inshore fish the conservation of seahorses, seadragons, and other Syngnathids has received the most attention globally. The conservation of Syngnathids has been largely driven by damage to inshore populations through collection for the world trade in seahorses for traditional medicines. International treaties have been created to limit the trade in seahorses.

Introductions of disease, exotic predators and competitors are occurring at an accelerating rate in the marine environment. Hopefully, quarantine will slow the introduction rate of these pests. Nevertheless, many of these pests are increasing their range. In the Derwent Estuary, Tasmania, Australia, the Spotted Handfish, Brachionichthys hirsutus, has been endangered by the introduction of the Northern Pacific sea star, Asterias amurensis. Hand fish are resident species in a few Tasmanian estuaries and lay few large eggs on the bottom, and the population of hand fish is under threat. Similarly, the European fan worm (sabellid) which has occupied large areas of Port Phillip Bay in Victoria, and which is now found in South Australia, may endanger inshore demersal fish. As the European fan worm feeds on zooplankton and replaces shelter, its effect on zoo-plankton feeders may be particularly detrimental with Syngnathids.

There have also been records of exotic crabs including established populations of the European Shore Crab - crabs are a major predator of Syngnathids . The invasive Caulerpa taxifolia also poses a clear threat to inshore fish. Mass strandings of the Common Seadragon, Phyllopteryx taeniolatus, were noted by 'Dragon Search, South Australia'. The cause of the strandings is not known but they corresponded to novel viral epidemics in other fish. The large scale stranding of seahorses occurred in South Australia in 2006. These prompted investigations that showed the species appeared to be a novel taxon and that similar strandings had occurred for some time, and may have occurred for decades.

Across southern Australia threats to Syngnathids have been attributed to species rarity (limited range and distribution), and the threat to their known habitat. The exceptions are the Leafy Seadragon and the Common Seadragon, spectacular species much loved by the diving community.

The seadragons have been, or are in the process of, being given conservation status. In South Australia all Syngnathids have recently been protected.

However, most of the Syngnathid species in Southern Australia have very few records, are often misidentified in museum collections, and their habitat and distribution are uncertain. For example one of the most the most restricted pipefish species, the Southern Gulf Pipefish (in description) in southern Australia, was not recognised until 2003. This species appears to only inhabit close inshore areas that are particularly vulnerable to modification during coastal development.