Philippine Crocodile Conservation in the Philippines
By Ben S. Malayang III, President
(Keynote Address delivered during the Forum on Crocodiles in the Philippines, 31 January to 2 February 2007, Museum of the Filipino People, Manila.)
There are compelling scientific, cultural and ecological reasons for why we need to more fully understand crocodiles, and thus why this conference would be significant.
Crocodiles including alligators, crocodiles, caimans, and gharials, are important because among the ancient species in our vertebrate biodiversity, they are the only remaining links to the past 200 million years, during which time their ancestral stocks evolved on the major continents of the world. The two species of crocodiles in the Philippines (the Indo-Pacific Crocodile and the Philippine Crocodile) probably attained their present species status during or before the Pleistocene, at least a million years ago. It is a Filipino social and cultural value to respect and appreciate the old, and so we are compelled to extend these cultural traits to these early inhabitants of our land.
The other characteristic of crocodiles that make them important to us is their contribution to natural productivity and thus to human well being. Without touching on the more practical uses of crocodiles in trade and industry, we can stress the ecological importance of crocodiles. Based on the keystone species concept first enunciated by the American ecologist R. Paine, who found that certain species determine the structure and function of communities, crocodiles in the Philippines serve as one group of such species in forest streams and river systems. The recycle nutrients between land and aquatic ecosystems, thus making these ecosystems productive of fish and other animals serving as food for humans. The German scientist E.J. Fittkau showed that fish catches in central Amazon forest streams decreased when the population of large carnivores (caimans) declined. He explained this finding by postulating a direct link between primary productivity (resulting in reduced top carnivores) and lack of nutrients recycled by the caimans. I understand that based on this hypothesis, our two species of crocodiles may be ecologically equivalent to a hundred or so smaller reptilian species in terms of impact on nutrient cycling.
It is probable that in the past, the two species of crocodiles in the Philippines, being the only large, amphibious animals in river systems of the country, performed an important function in aquatic (freshwater and marine) habitats by recycling the nutrients between the aquatic habitats across different tropic levels. The ultimate result was abundance of aquatic species, especially fish, in these habitats. It is unfortunate that, except for some areas on Mindanao (part of the Ligawasan Marsh), the opportunity to scientifically verify Fittkau’s hypothesis has been lost. The disappearance of the crocodiles would appear to be one major contributory factor to the demise of our large river systems.
Having explained the scientific, cultural and ecological importance of crocodiles, let me now touch on the efforts of some groups to conserve crocodiles with particular emphasis on the endemic Philippine Crocodile.
Crocodiles are reptiles, which, together with other reptiles and the amphibians, constitute the vertebrate group referred to as herpetofauna and studied by specialists in the science of herpetology. Reptiles make up about one-third of the total species of land vertebrates, which currently is about 1,100 species. Herpetologists and naturalists have studied Philippine herpetofauna since 1839. Between 1839 and 1906, these studies were made by foreign scientists (mainly British) on Philippine specimen collections deposited in the British Museum. The American herpetologist E.D. Taylor at the University of Kansas was the first herpetologist to study in depth Philippine herpetofauna between 1915 and 1925. Taylor was followed by R.F. Inger in 1956, W.C. Brown (Stanford University and Menlo College), A. Leviton (California Academy of Sciences), C.A. Ross (Smithsonian Institution) and A.C. Alcala (Silliman University) from 1955 to 2000s; and R. Brown (University of Kansas), A. Diesmos (National Museum), and Roger Sison (National Museum) from late 1990s to the present.
However, none of the scientists listed above made studies on crocodiles except C.A. Ross and A.C. Alcala. It is difficult to say why this is so. I think one reason is that crocodile studies entail a lot of careful fieldwork, and is certainly more involved than, say, studying smaller species in the laboratory.
One of the earliest scientific studies on the Philippine Crocodile was made at Silliman and was concerned mainly with captive breeding of this species in the Crocodile Breeding Facility established in 1980, the first such Facility in the Philippines. (The Crocodile Farming Institute was established by DENR and JICA in 1987; JICA support was extended through 1994.) The objective of the Silliman Facility was conservation of the Philippine Crocodile. The plan was to release the offspring for breeding purposes and for re-stocking of depleted habitats.
The breeding program was successful. The female laid eggs every year from 1981 to 1994, producing some 354 eggs, of which 114 hatched successfully. Twenty-one individuals from these hatchlings are currently in the Facility and the rest have been dispersed. This study documented for the first time the behavior of this species in captivity, including parental care (similar to that described for other species of the genus Crocodylus). The study also showed the non-aggressive nature of the species; an female even got used to being tickled while feeding.
The female crocodile, caught as juvenile (ca one year old) in Pagatban River, southern Negros, was donated to the Facility by Silliman Anthropology professor Timoteo Oracion in 1972. The male was donated to the Facility by a Zamboanga City resident through the effort of Charles A. Ross in 1980 and was probably 15 years old at that time.
The Facility has received a grant in 2006 from Coral Farms Inc. (a private sector) to construct more breeding and holding pens and to fund a graduate student to monitor and observe crocodile behavior under captive and semi-wild conditions. In addition, ecological studies on both captive and wild populations will be conducted by the SUAKCREM under the directorship of A.C. Alcala. Progeny of the captive breeding program will be released to suitable and previously identified protected habitats by Coral Farms Inc. and Silliman University.
Conservation of the Philippine Crocodile is as urgent now as it was in the early 1980s when Charles Ross, then at the Smithsonian Institution, Washington, D.C. made the first attempt to survey the population status of the Critically Endangered Philippine Crocodile. Ross reported between 500 and 1000 individuals in the wild and several captive animals in private hands. This situation now is not much different from what was in the 1980s, despite the crocodile recovery plan and the discovery of several individuals in the San Mariano area, Isabela Province and in Abra province, both in northern Luzon, as well as the confirmation of the presence of a population of unknown size in the Ligawasan Marsh, in the vicinity of the Kabacan municipality, Mindanao Island and a report of an individual on Dalupiri Island, the Babuyan Group. We still do not know much about the ecology of the Philippine Crocodile, except for an insight into the behavior of this species that could set it apart from other Crocodylus species thus far known. The program at the Silliman Crocodile Facility includes finer investigations into the ecology and behavior of the Philippine Crocodile under wild and captive conditions, which began in the 1980s but which was interrupted by other herpetological concerns.
Aside from Luzon and Mindanao Islands, the historical record of the geographical distribution of the Philippine Crocodile includes Mindoro, Samar, Masbate, Negros, Jolo, and Busuanga. It has also been reported on the island of Dalupiri, the Babuyan Group of Islands off northern Luzon. Its specifies name mindorensis was given by Karl P. Schmidt, late Curator of Herpetology, Field Museum, Chicago based on material from Mindoro Island. It has been assumed that the species is found in Naujan Lake, but thus far it has not been recorded from this lake.
The Crocodile Farming Institute (CFI) has had success in breeding both the Indo-Pacific Crocodile and the Philippine Crocodile by several hundreds. However, as of now, much needs to be done to realize the commercial objective for the Indo-Pacific species. The conservation objective for the Philippine Crocodile also needs more effort to attain full realization. This is mainly because of the refusal of people living around a lake in northern Palawan to allow the introduction of captive-bred Philippine Crocodiles hatched and reared in the CFI. This failure indicates that much more is required than table planning for projects dealing with crocodile introductions or re-introduction.
One possible solution would be to develop partnerships with the private sectors which have businesses that can provide food and marshy areas suitable as crocodile habitats. The important thing is to conserve the animals that are in the wild and those that have been bred in the CFI so that Crocodylus mindorensis, the only Philippine endemic crocodile and also one of the most endangered crocodilians in the world, can survive in the future.
My hope is that in this Forum, you will decide on ways to enable our endemic species of crocodile to survive in some aquatic habitats free from human disturbance so that the species can be further studied and can function to serve the needs of other species including us.