Distributions of Fishes in Fresh Water of 



Katmai National Monument, Alaska, and 



Their Zoogeographical Implications 



By 



WILLIAM R. heard/ RICHARD L. WALLACE,^ 

 and WILBUR L. HARTMAN^ 



ABSTRACT 



Katmai National Monument covers 10,916 km.^ on the base of the Alaska Penin- 

 sula and is divided by the Aleutian Mountain Range into two principal drainage areas. 

 Streams north of the Aleutian Range flow into Bristol Bay of the Bering Sea, and 

 those south of the mountains flow into Shelikof Strait of the North Pacific Ocean. 

 The large multilake Naknek River system is the dominant drainage area on the 

 Bristol Bay side of the monument, whereas small single lakes and short streams 

 and rivers constitute many separate drainages on the Shelikof Strait side. Twenty- 

 four species of fish occur in the Bristol Bay drainages of the monument, but only 

 eight species were collected in streams and lakes draining into Shelikof Strait. Evi- 

 dently the Aleutian Range has been a barrier to the southward movement of fresh- 

 water fishes in the monument. All eight species in Shelikof Strait drainages are 

 capable of dispersal through salt water, whereas several forms in Bristol Bay 

 drainages require fresh water for dispersal. Variable numbers of species occur in 

 the interconnecting lakes of the Naknek River system. Naknek Lake, the downstream 

 terminus of the lake system, contains 24 known species and each upstream lake 

 contains fewer species than the one into which it drains. The present distribution 

 of fishes in this system is discussed in terms of the sequential timing of species 

 invasion and the postglacial development of barriers. 



INTRODUCTION 



Katmai National Monument is at the base of 

 the Alaska Peninsula in southwestern Alaska 

 {fig. 1). It was established by Presidential 

 Proclamation in 1918, primarily to preserve 

 the spectacular features of the Valley of Ten 

 Thousand Smokes --a volcanic phenomenon that 

 resulted in 1912 from the eruption of the vol- 

 cano Mt. Novarupta. In subsequent years the 

 boundaries were extended to include much of 

 the area surrounding the Valley of Ten Thou- 

 sand Smokes, and the monunient now encom- 

 passes 10,916 km.^. Interesting accounts of 

 the discovery, description, and history of this 

 remote scenic area were given by Griggs 

 (1922) and Cahalane (1959). 



The monument has many prominent fea- 

 tures that influence the distribution of fishes. 

 It is divided by the Aleutian Range along a 

 northeast -southwest axis so that the general 

 streamflow is to the sides of the Alaska Penin- 



^ Fishery Biologist, Bureau of Commercial Fisheries 

 Biological Laboratory, Auke Bay, Alaska 99821. 



^ Graduate student. Department of Fisheries and Wild- 

 life, Oregon State University, Corvallls, Oreg. 97331. 



sula. The area has a long history of volcanism 

 (Wahrhaftig, 1965), and glaciation was exten- 

 sive during the Pleistocene (MuUer, 1952; 

 Karlstrom, 1957). Several streams on each 

 slope of the Aleutian Range still originate 

 from small, vestigial glaciers. One of the most 

 important features influencing the distribution 

 of fishes in the monument is the large complex 

 of interconnecting streams and lakes in the 

 Naknek River system. This system dominates 

 the western half of the monument; it is here 

 the Bureau of Commercial Fisheries has a 

 cooperative arrangement with the National 

 Park Service to do biological research on 

 sockeye salmon, Oncorhynchus nerka (Wal. 

 baum). This research began at Brooks Lake 

 in 1940 and was expanded in 1961 to include 

 all of the Naknek system. Some of the studies 

 have dealt with fishes associated with sockeye 

 salmon. 



We have been involved with various aspects 

 of studies at Brooks Lake since 1957 and 

 throughout the Naknek system since 1961. In 

 1962, we began to collect fishes from other 

 drainage systems in the monument. 



