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Status of Nile Crocodile (Crocodylus niloticus) in Ethiopia and its Role as Biometrology Indicator

Melaku Tefera, College of Veterinary Medicine, Haramaya University, P.O.Box 144 Haramaya Campus. Ethiopia. 251-0914722459, <melaku22@yahoo.com>

Melaku Tefera

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Evolution of Climate and Crocodile

A region's climate is generated by the climate system, which has five components: atmosphere, hydrosphere, cryosphere, geosphere, and biosphere

The primary role of oceans in all this is in providing barriers to dispersal

Continental drift and the unique time-sequence of lineage origination, then, are what explain the existence of what we call the zoogeographical realms.

About 250mya all the ocean were one

Pangaea and Continental drift

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Photos/Illustration: National Park Service, Randal Irmis, Gautam Rangan, Randal Irmis/Andrew Lee/Nick Pyenson

Evolutionary tree of dinosaurs and crocodiles

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Crocodile as Successful Survivor

Cretaceous–Tertiary extinction event

Cretaceous–Paleogene (or K–Pg) extinction

K–T extinction event, it is associated with a geological signature known variously as the k-T boundary , the Cretaceous–Paleogene boundary or the K–Pg boundary, usually a thin band of sedimentation visible wherever rocks of this age are exposed

volcanism, marine regression and extraterrestrial impact

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Mass Extinction Events the Big Five

Timeline of mass extinction events. The five named vertical bars indicate mass extinction events. Black rectangles (drawn to scale) represent global reef gaps and brick-pattern shapes show times of prolific reef growth (Veron ,2008)

Global drop in sea level Deep-ocean anoxia Glaciation? Depletion of oxygen in marine waters

Phanerozoic

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Nile Crocodile Taxonomy

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Distribution of Crocodile in Ethiopia

2.6 billion cubic meters per year Renewable groundwater 122 billion cubic meters per year

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Crocodile and River Basins

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Crocodile and Major Lakes

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Lake Altitude(m)

Area(km²)

Mean depth (m) Crocodiles

Rift ValleyChamo 1 280 550 13.0 +

Abaya 1 285 1 160 7.1 +Awassa 1 710 90 11.6 -Shala 1 570 410 8.6 +Langano 1 585 230 17.0 -Abijata 1 575 205 7.6 +Ziway 1 850 435 2.5 -Koka* na 255 9.0 +Other areasTana 1 830 3 500 8.0 ±Fincha* 2 160 170 9.0 -Hashenge - 7 005 -

Crocodile and Major Lakes

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Heavy hunting for skins began in the mid-1950s. In 1963 the French owned, Dofan Ethiopia Share Company had crocodile hunting concessions on several rivers and in 1966 Dofan established Modjo tannery

Crocodile status

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By 1971 Nile crocodile were seriously depleted. Subsequently, in 1972 commercial hunting of crocodiles was prohibited in Ethiopia

Ethiopia joined the Convention on International Trade in Endangered Species (CITES) which regulates trade in crocodile products, in 1988 and the Nile crocodile was transferred from Appendix I, the highest order of protection, to Appendix II to allow an export quota for ranched skins. The initial quotas approved by CITES were from 9,000 to 12,000 skins per year for export based on the ranching programme, though total skin sales since 1984 were less than 8,300.

CITES-IUCN

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1980-The crocodile ranch in Arba-Minch is built on the edge of Lake Abaya, in Ethiopia's southern Rift Valley, and is home to around 4,000 of the reptiles

Year No. Nests No. Eggs Average clutch size

Hatched Hatchlings to ranch

Hatchlings released

1985 4 129 32 72 72 Nil

1986 72 3176 44 2713 2713 Nil

1987 206 5521 27 4928 2622 2306

1988 132 4103 31 3510 2587 923

1990 265 7752 29 6244 6045 199

1991 74 2749 37 2121 2005 116

1997 242 5663 23 4011 4011 Nil

2001 58 2572 47 2120 2000 120

2004 262 11840 45 9400 8000 1400

Total 1607 53124 42755 37195 5559

Table. Egg collection data. Arbaminch crocodile ranch

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ARBAMIN CH

RANCH

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…Status Lake Chamo

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Country 2003 2004 2005 2006 2007 2008 2009 2010

Botswana 0 0 0 0 *320 *374 *1,626 *1,500

Brazil 1 44 0 0 0 0 0 0

Ethiopia 900 300 347 727 *594 492 0 4

Israel 0 0 0 0 0 0 *2 0

Kenya *1,687 2,850 9,550 8,710 6,354 4,504 4,283 4,309

Madagascar 7,300 4,760 4,850 6,660 5,500 2,640 2,450 0

Malawi 301 *100 *1,038 698 *1,350 3,370 2,603 *500

Mali 0 0 0 0 0 107 0 0

Mauritius 118 400 150 184 231 189 100 0

Mozambique 3,160 0 1,156 2,000 179 566 0 2,449

Namibia 0 0 400 305 0 0 600 2

South Africa 31,321 35,760 35,486 34,203 36,014 44,697 25,050 47,267

Uganda 600 600 *600 *300 0 *290 0 *500

Tanzania *1,439 *1,067 *1,584 *1,100 *1,556 *1,784 1,365 601

Zambia 28,019 26,353 *33,184 *42,266 *44,597 28,197 43,655 23,717

Zimbabwe® 73,707 68,263 63,146 71,616 64,490 81,554 67,350 80,995

Total 148,553 140,497 151,491 168,769 161,185 168,764 149,082 161,840

Crocodile Skin supply from Africa

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18Key -Stone Species

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Bioindicator

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BIO-METEROLOGY•Temperature regulation is a dynamic process that involves behavioral and physiological adjustments.

•The consequences of devoting time to thermoregulation have broad behavioral and ecological significance. The time spent in thermoregulation can sometimes reduce the time available for other important activities (Huey, 1982). Climatic conditions, social interactions Land water movement is triggered by - Circadian rhythm

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Lack of thorough scientific study, combined with a misunderstanding of this species, remains the biggest threat to Nile crocodiles

Habitat lossfragmentation of natural habitats .The loss of swamps, marshes, wetlands and other natural systems into agriculture, mines, and urban developments, the draining of swamps and other wetlands, Dam construction

Hunting and exploitationPersecution and trophy huntingPeople have long considered crocodiles vermin or a dangerous nuisance. For this reason, crocodiles have been hunted to extinction in some placesConflict with humans presents perhaps the greatest threat to the Nile crocodile. As large and potentially dangerous predators, people are often, understandably, intolerant of crocodiles, and deliberate destruction of nests and killing of adults is common . Crocodiles may also come into conflict with fishermen, damaging nets when trying to remove fish from them

Pollution

Critical Threats

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Temperature Dependent Sex Determination

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Community-Based Wildlife Management (CWM)

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By focusing narrowly on economic incentives, conservationistsrisk undermining their credibility and obscuring other valid reasons to protectnature.

EducationCultural and intrinsic values, respect for nature, interest in wildlife ecology and pride in the occurrence and conservation of a rare and iconic species can also form a strong motivation

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Thank you!