Bird migration and the spread of Crustacea. [Translation from: Verhandlungen der Deutschen Zoologischen Gesellschaft 27, 311-316, 1963.]

The passive spread of a high percentage of freshwater organisms is one of the most important requirements in short-lived and insular communities for species to attai n and survive - and consequently to balance the lack of a topographical continuity of most inland waters. Unfortunately hardly anything is known about the amounts of seed material typical for any lake into which it is carried. The causes of passive dissemination - wind, water and animals as well as man - are confirmed by many examples. It has been assumed now for at least a hundered years that , among animals, birds play a prominent role, although also disappointingly few facts are at hand. The passage and spread through birds' intestines has up to now been supported only by some limited data. This paper reports on experimental research where the eggs of Daphnia magna, Triops cancriformis, Artemia salina, Diaptomus spinosus and Cypris pubera were introduced by means of gelatine capsules into the oesophagus of a drake. The bird's excrements were inspected under a microscope for eggs and resting stages, and these were transferred into corresponding cultures.

Vegetation response to cattail management at Cheyenne Bottoms, Kansas

Dense, monospecific cattail (Typha spp.) stands are a problem in many prairie wetlands because they alter habitat structure and function, resulting in a decrease in use by wildlife species. Cheyenne Bottoms Wildlife Area, a Wetland of International Importance in central Kansas, has experienced a large increase in cattails and a subsequent decrease in migratory wetland bird use. As a consequence, intensive cattail management is practiced. We assessed the effectiveness of prescribed burning, discing following prescribed burning, and cattle grazing following prescribed burning at two stocking rates of 5 and 20 head per 11 ha in suppressing cattail, as well as the effects of these treatments on non-cattail vegetation.

Miscellaneous studies

MISCELLANEOUS STUDIES, which includes the following papers: "Geology of the Area in and Around the Jim Woodruff Reservoir" by Charles W. Hendry, Jr. and J. William Yon, Jr.; "Phosphate Concentrations near Bird Rookeries in South Florida" by Dr. Ernest H. Lund, Department of Geology, Florida State University; and "An Analysis of Ochlockonee River Channel Sediments" by Dr. Ernest H. Lund, Associate Professor and Patrick C. Haley, Graduate Assistant, Department of Geology, Florida State University. (PDF contains 81 pages)

A Comparison of Two Methods for Enhancing the Recovery of Seagrasses into Propellor Scars: Mechanical Injection of a Nutrient and Growth Hormone Solution vs. Defecation by Roosting Seabirds: Final Report.

Based on the recovery rates for Thalassia testudinum measured in this study for scars of these excavation depths and assuming a linear recovery horizon, we estimate that it would take ~ 6.9 years (95% CI. = 5.4 to 9.6 years) for T. testudinum to return to the same density as recorded for the adjacent undisturbed population. The application of water soluble fertilizers and plant growth hormones by mechanical injection into the sediments adjacent to ten propellor scars at Lignumvitae State Botanical Site did not significantly increase the recovery rate of Thalassia testudinum or Halodule wrightii. An alternative method of fertilization and restoration of propellor scars was also tested by a using a method of “compressed succession” where Halodule wrightii is substituted for T. testudinum in the initial stages of restoration. Bird roosting stakes were placed among H.wrightii bare root plantings in prop scars to facilitate the defecation of nitrogen and phosphorus enriched feces. In contrast to the fertilizer injection method, the bird stakes produced extremely high recovery rates of transplanted H. wrightii. We conclude that use of a fertilizer/hormone injection machine in the manner described here is not a feasible means of enhancing T. testudinum recovery in propellor scars on soft bottom carbonate sediments. Existing techniques such as the bird stake approach provide a reliable, and inexpensive alternative method that should be considered for application to restoration of seagrasses in these environments. Document contains 40 pages)

Accelerating loss of seagrasses across the globe threatens coastal ecosystems

Coastal ecosystems and the services they provide are adversely affected by a wide variety of human activities. In particular, seagrass meadows are negatively affected by impacts accruing from the billion or more people who live within 50 km of them. Seagrass meadows provide important ecosystem services, including an estimated $1.9 trillion per year in the form of nutrient cycling; an order of magnitude enhancement of coral reef fish productivity; a habitat for thousands of fish, bird, and invertebrate species; and a major food source for endangered dugong, manatee, and green turtle. Although individual impacts from coastal development, degraded water quality, and climate change have been documented, there has been no quantitative global assessment of seagrass loss until now. Our comprehensive global assessment of 215 studies found that seagrasses have been disappearing at a rate of 110 square kilometers per year since 1980 and that 29% of the known areal extent has disappeared since seagrass areas were initially recorded in 1879. Furthermore, rates of decline have accelerated from a median of 0.9% per year before 1940 to 7% per year since 1990. Seagrass loss rates are comparable to those reported for mangroves, coral reefs, and tropical rainforests and place seagrass meadows among the most threatened ecosystems on earth.

Fischbestände der Ostsee, ihre Entwicklung seit 1970 und Schlussfolgerungen für ihre fischereiliche Nutzung - Teil 3: Sprotte

The sprat of the Baltic Sea is not as short-lived as inother Seas probably because fish predator species arerestricted mainly on cod and salmon. Sea bird popula-tions are much smaller and marine mammals are rare inthe Baltic Sea. The sprat stock biomass is fluctuatingstrongly. The fluctuation is mainly influenced by thestock recruitment and is also dependent on the strengthof the cod stock. After a strong decrease during the1980ies sprat catches increased again from 1992 onwardsand reached a peak with over half a million tonnes in 1997. At about the same time the character of the BalticSea sprat fishery changed from catches mainly for hu-man consumption to catches mainly for industrial pur-poses initiated by the fishery of Sweden. The recentrecord high catches of sprat have been possible only dueto the low level of the cod stock of the main Baltic SeaBasins over some years. A sprat fishery on such a highcatch level might cause conflicts with a recovering codstock in future.

Fischereitechnische Forschung für eine selektive, umweltverträgliche und energiesparende Fischerei

On 1st March 1995, the name of the former "Institut für Fangtechnik" ("Institute for Fishing Techniques") at the Federal Research Centre for Fisheries in Hamburg has been changed into "Institut für Fischereitechnik" ("Institute for Fishery Techniques"). The new conception and structure of this institute are described. Aims and possibilities of research in fishing techniques as a contribution for a selective, environment friendly and energy saving fishery are illustrated by examples in Baltic cod and eel fishery and also sea-bird bycatches, crangon fishery in the North Sea, and possible substitutions for technologies with high fuel consumption by energy saving technologies as longlining, gillnetting and anchored pound nets.

A survey of aquatic invertebrates of the Somerset Levels, August 13-14, 1981

Since 1975 the wildlife interest of the Somerset Levels and Moors have been assessed. Detailed information has been obtained on the conservation interest of meadows, breeding and wintering bird populations and the botany of aquatic habitats (rhynes). Little work to date has been carried out on the terrestrial and aquatic invertebrate fauna. The prime aim of this survey was to sample a wide variety of rhynes in order to obtain information on the nature and distribution of aquatic invertebrates.

Sternes réprises en Côte d'Ivoire au cours des hivernages 1973-1974 et 1974-1975

Data are reported on: (1) date and place of ringing the juveniles and adults of the sea bird of the genus Sterna in Côte d'Ivoire, and (2) date and place of recapture during the winter periods of 1973-74 and 1974-75.

Sternes réprises en Côte d'Ivoire au cours des derniers hivernages des années 1969-1970-1971-1972-1973

Data are reported on: (1) date and place of ringing the juveniles and adults of the sea bird of the genus Sterna in Côte d'Ivoire, and (2) date and place of recapture during the winter periods of 1969, 1970, 1971, 1972, 1973.

Avian piscivores: basis for policy.

In Britain, many birds eat fish in fresh waters but only three species, cormorant, red-breasted merganser and goosander, are commonly perceived to present serious problems for freshwater fisheries. Complaints are mainly that cormorants eat large fish and that all three bird species eat so many juvenile fish, that there are subsequently fewer fish to be harvested or angled, but also that persistent predation by birds changes fish behaviour so that they are less 'catchable'. To this end, this report reviews existing information on the current status, foraging ecology, and population biology of the three bird species as background to their potential impact on fisheries. Discusses fish population dynamics within the context of predation effects. Reviews existing experimental evidence for impacts on fish populations and fisheries; and describes current legislation, discusses potential criteria for serious damage to a fishery, and suggests ways forward for NRA policy and research.

Relative importance of various predators in Clarias gariepinus fry mortality in Cameroon

To estimate the relative importance of the most common predators of Clarias gariepinus fry, increasing levels of protection were afforded to exclude amphibians, aquatic arthropods and birds. At a stocking density of 10 larvae/sq.m. in nursing ponds, fencing off amphibians resulted in a 28 per cent decrease in mortality. Holding fry in hapas to protect them from both amphibians and aquatic arthropods decreased mortality by an insignificant 5.7 per cent. Installation of bird-netting over the hapas reduced mortality by 21.7 per cent. The remaining 4.9 per cent of total mortality, which could not be explained, was attributed to opportunistic cannibalism, disease and/or handling stress. Increasing stocking density to 40/sq. m. and, thus, reducing the food available per fry increased mortality by 28.3 per cent.

Ecology and growth of juvenile California spiny lobster, Panulirus interruptus (Randall)

ABSTRACT TRANSCRIBED FROM ENGLE'S PH.D. ORAL DEFENSE PAMPHLET: The natural history of juvenile California spiny lobster, Panulirus interruptus (Randall), was investigated, with primary emphasis placed on ascertaining juvenile habitats, determining juvenile growth rates and component growth processes, and evaluating ecological and behavioral phenomena associated with juvenile survival and growth. Habitat surveys of island and mainland localities throughout southern and lower California revealed that small, greenish juveniles typically inhabit crevices or temporary burrows in 0-4m deep, wave-swept rocky habitats covered by dense beds of surf grass, Phyllospadix torreyi S. Watson. Phyllospadix beds were more abundant on gradually sloping rocky mainland beaches than on steeply sloping island shores. Phyllospadix abundance was positively correlated with P. interruptus abundance; however, at Santa Catalina Island, the Phyllospadix habitat was not extensive enough to be the sole lobster nursery. In laboratory tests, puerulus larvae and early juveniles chose Phyllospadix over rubble rocks or broad-bladed kelp, but did not consistently prefer Phyllospadix over reticulate algae. Ecology, growth, and behavior of juvenile P. interruptus inhabiting a discrete Phyllospadix habitat at Bird Rock, Santa Catalina Island, were investigated from October 1974 through December 1976 by means of frequent scuba surveys. Pueruli settled from June to November. Peak recruitment occurred from July to September, when seasonal temperatures were maximal. Settled larvae were approximately one year old. Juvenile growth was determined by size-frequency, single molt increment, mark-recapture, and laboratory culture studies. Carapace length vs. wet weight relationships fit standard power curve equations. Bird Rock juveniles grew from 7 to 32mm CL in 10-11 molts and from 32 to 56mm CL in 5-6 molts during their first and second benthic years, respectively. Growth rates were similar for males and females. Juveniles regenerating more than two limbs grew less per molt than intact lobsters. Long-term growth of laboratory-reared juveniles was 20% less than that of field lobsters. Growth component multiple regression analyses demonstrated that molt increment was directly proportional to premolt size and temperature for age 1+ lobsters. Molt frequency was inversely proportional to size and directly proportional to temperature. Temperature affected age 2+ lobsters similarly, but molt increment was independent of size, and molt frequency declined at a different rate. Juvenile growth rates more than doubled during warm water months compared to cold water months, primarily because of increased molt frequency. Based on results from this study and from previous investigations, it is estimated that P. interruptus males and females become sexually mature by ages 4 and 5 years, respectively, and that legai size is reached by 7 or 8 years of age. Juvenile P. interruptus activity patterns and foraging behavior were similar to those of adults, except that juvenile home ranges were proportionally smaller, and small juveniles were apparently not attracted to distant food. Small mollusks, abundant in Phyllospadix habitats, were the major food items. Size-dependent predation by fish and octopus apparently caused the considerable juvenile mortality observed at Bird Rock. Juveniles approaching 2 years of age gathered in mixed size-class aggregations by day and foraged beyond the grass beds at night. In autumn, these juveniles migrated to deeper habitats, coincident with new puerulus settlement in the Phyllospadix beds. Based on strong inferences from the results, it is proposed that size-dependent predation is the most important factor determining the !ife history strategy of juvenile P. interruptus. Life history tactics promoting rapid growth apparently function dually in reducing the period of high vulnerability to predation and decreasing the time required to reach sexual maturity. The Phyllospadix habitat is an excellent lobster nursery because it provides shelter from predators and possesses abundant food resources for sustaining optimum juvenile growth rates in shallow, warm water.