Food capture and escape behavior of Leposternon microcephalum Wagler, 1824 (Squamata: Amphisbaenia)

Amphisbaenians are fossorial reptiles that have a cylindrical and elongated body covered with scales arranged in rings, and are all apodal, except for the three species of the genus Bipes. The amphisbaenian diet consists of a variety of invertebrates and small vertebrates. As these animals live underground, many aspects of their natural history are difficult to study. Most feeding studies of amphisbaenians have focused on the composition of the diet and feeding ecology, and the data available on feeding behavior are based on precursory observations. The present study describes the food capture behavior of Leposternon microcephalum Wagler, 1824 in captivity. In this experiment we used non-live bait (moist cat food), which was placed near a burrow opening, on the surface of the substrate. Three animals were monitored visually and filmed using cellphone cameras deployed at fixed points, to capture images from the dorsal and lateral perspectives of the study subjects. Two principal types of behavior were observed: the capture of food and defense mechanisms. The strategies used to capture the food were similar to those observed in other fossorial species. Although the backward movement has already been observed and described, we were able to record this movement being used as an escape strategy. These findings enrich our knowledge on different aspects of the natural history of the amphisbaenians.

Widespread anthropogenic translocation of the African Clawed Frog across its native range is revealed by its co-introduced monogenean parasite in a co-phylogeographic approach

1. The management of biological invasions relies upon the development of methods to trace their origin and expansion. Co-introduced parasites, especially monogenean flatworms, are ideal tags for the movement of their invasive hosts due to their short generations, direct life cycles and host specificity. However, they are yet to be applied to trace the intraspecific movement of species in their native ranges. 2. As proof of this concept, we conducted a co-phylogeographic analysis based upon two mitochondrial markers of a globally distributed frog Xenopus laevis and its monogenean flatworm parasite Protopolystoma xenopodis in both its native range in southern Africa and its invasive range in Europe. 3. Translocation of lineages was largely masked in the frog's phylogeography. However, incongruent links between host and parasite phylogeography indicated host switches from one host lineage to the other after these were brought into contact due to human-mediated translocation in the native range. Thus, past translocation of host lineages is revealed by the invasion success of its co-introduced parasite lineage. 4. This study demonstrates the concept that parasite data can serve as an independent line of evidence in invasion biology, also on the intraspecific level, shedding light on previously undetected invasion dynamics. Based upon the distribution of these invasive parasite lineages, we infer that the widespread translocation of hosts is mainly facilitated by the frog's use as live bait by the local angling communities and not via official export routes. 5. Data from co-introduced, host-specific parasites can add value to investigations in invasion biology and conservation. A better understanding of the translocation history and resulting genetic mixing of animals in their native ranges prior to introduction into new environments can inform management strategies in the invasive range. Knowledge of the intraspecific movement of different lineages of animals in their native ranges also has conservation implications, since contact between divergent lineages of hosts and parasites can facilitate host switches and altered parasite dynamics in both native and invasive populations. Therefore, we recommend the inclusion of parasite data as a more holistic approach to the invasion ecology of animals on the intraspecific level.

LIVE BAIT TRADE AS A PATHWAY FOR THE INTRODUCTION OF NON-NATIVE SPECIES: THE FIRST RECORD OF Dilocarcinus pagei IN THE PARANAPANEMA RIVER BASIN

Brazil has one of the most significant diversity of freshwater fish in the world, and this drives trade and fishing tourism. Several species of sport fish have characteristics and behaviors that favor fishing tourism and its related activities. Live baits are widely used in fisheries across the country, and at the end of fisheries, is common that anglers may release the remaining bait in rivers, lakes or reservoirs. Here we report for the first time the crab Dilocarcinus pagei in the Paranapanema River basin, and list the freshwater species that were introduced similarly. During field samplings between 2012/2016, and 2018/2019, we captured 10 individuals of D. pagei. One female in the Rosana Reservoir; and two juveniles, one female and six males in the Taquaruçu Reservoir. The literature review revealed 16 species used as live bait, the crab D. pagei and 15 fish species. Gymnotiformes were the largest number of species used as live bait. The basins that had introduction cases were in the Upper Paraná, Iguaçu, and Paraíba do Sul Rivers. The Paraguay-Lower Paraná River was the system that contributed with nine species to the most invaded ecoregion in Brazil, the Upper Paraná River basin. Anglers and live bait farmers should be aware of the risks and consequences of these constant introduction actions (propagule pressure), not releasing baits. In addition, the live bait trade must be monitored and controlled to occur only with species in their original river basin.

Nightcrawler commodities: A brief history on the commodification of the humble dew worm

Each year, 500 to 700 million dew worms are sold from thousands of gas stations, convenience stores, big box retailers, making this particular species, Lumbricus terrestris, the most popular live bait for recreational freshwater fisherman across North America. In fishing parlance, these effective bait worms are referred to as “Canadian Nightcrawlers,” not because they are native to the region (they are not) or because they cannot be found elsewhere (they can), but because the entire global supply comes from a stretch of rural land between Toronto and Windsor in Ontario, Canada. How did this simple garden worm become a valuable commodity, and why is production relegated to one single region in the world? In this paper, I rely on newspaper archives and key informant interviews to construct a “capitalist commodification story” that explain why demand for Canadian Nightcrawlers emerged in North America, why the production of nightcrawlers is relegated to southwestern Ontario, and how this lowly living, breathing, squirming creature beneath our feet became a capitalist commodity producing value through competitive markets. In sum, I argue L. terrestris became a capitalist commodity when burgeoning demand from a new class of recreational fishermen increased competition between nightcrawler suppliers. The inability of capital to take hold of the ecological conditions of nightcrawler production relegated the most productive producers to southwestern Ontario who had the contingent privileges of useful soils combined and cheap and efficient labor. The materiality of L. terrestris physiology is thus constitutive of how capital seeks to accumulate surplus value in a peculiar industry. At the same time, this research shows that no matter how peculiar or banal a commodity may be capitalist logics are constantly experimenting with heterogenous peoples and environments to find a way to increase productivity and accumulate surplus value through market exchange.

Histological Observation Of Milkfish Organs With Stunting Phenomenon

Milkfish (Chanos chanos) is an important economic fish. Milkfish is widely consumed because it has high nutritional value. Milkfish is also used as live bait for fishing. In the milkfish cultivation system, increasing production is a very important factor. One of the efforts to increase production in fish farming systems is the application of high stocking density. Constraints to the application of the high stocking density cause the growth of milkfish to be non-uniform, some of them even experience stunting, which is a condition in which the fish experience slow growth. This study aims to observe the condition of the milkfish tissue with normal growth and stunted fish. Milkfish (Chanos chanos) used are fish that have been reared for 6 months. Fish organs that were sampled for observation were stunted and normal (non-stunting) fish. The organs observed were the gills, muscles, and intestines. The results showed that stunted milkfish (Chanos chanos) affected the condition of the gill tissue, muscles, and intestines. The gills are edema and necrosis. Muscles undergo edema, degeneration of muscle fibers, and necrosis. The intestine experiences necrosis or cell death.Keywords: Milkfish; Stunting; Histology.AbstrakIkan Bandeng (Chanos chanos) merupakan ikan bernilai ekonomis penting. Ikan Bandeng banyak dikonsumsi karena mempunyai nilai gizi yang tinggi. Ikan bandeng juga dimanfaatkan sebagai umpan hidup untuk penangkapan ikan. Pada sistem budidaya ikan Bandeng peningkatan produksi menjadi faktor yang sangat penting. Salah satu upaya peningkatan produksi pada sistem budidaya ikan adalah dengan aplikasi padat tebar yang tinggi. Kendala penerapan padat penebaran yang tinggi menyebabkan pertumbuhan ikan Bandeng tidak seragam, bahkan beberapa diantaranya mengalami stunting yang merupakan suatu kondisi dimana ikan mengalami lambatnya pertumbuhan. Penelitian ini, bertujuan untuk mengamati kondisi jaringan ikan bandeng dengan pertumbuhan normal dan ikan yang mengalami stunting. Ikan Bandeng (Chanos chanos) yang digunakan adalah ikan yang telah dipelihara selama 6 bulan. Organ ikan yang menjadi sampel pengamatan adalah ikan yang mengalami stunting dan normal (non-stunting). Organ yang diamati adalah insang, otot, dan usus. Hasil penelitian menunjukan ikan Bandeng (Chanos chanos) yang mengalami stunting mempengaruhi kondisi jaringan insang, otot dan usus. Insang mengalami edema dan necrosis. Otot mengamali edema, degenerasi serabut otot, dan necrosis. Usus mengalami necrosis atau kematian sel.Kata kunci: Ikan Bandeng, Stunting, Histologi

Fishing on Porpoise

Since the late 1950s, millions of dolphins have died as bycatch in the American yellowfin tuna industry. These deaths were not caused by accidental incidents between humans and dolphins, but rather were the result of a common fishing method used to catch yellowfin tuna that fishermen called “porpoise fishing” or “fishing on porpoise.” Although fishermen had caught tuna alongside dolphins since the 1930s, mass dolphin bycatch did not begin until the late 1950s, when the fleet converted from live-bait pole-and-line fishing to purse seining. This conversion—labeled the “purse-seine revolution”—occurred in response to economic and geopolitical pressures that threatened the future of the industry and was made possible by technological advancements that made purse seining a more effective method for catching yellowfin tuna. This conversion fundamentally altered the relationship between fishermen and dolphins. This article argues that the origins of mass dolphin bycatch are rooted in the purse-seine revolution and lie in the nexus of the economic, geopolitical, and technological developments that led to this conversion.

MORPHOMETRICS OF JUVENILE WHITE SHRIMP IN SANTOS (SP, BRAZIL) - AN ATLANTIC STRESSED ESTUARY

Shrimps are one of the world’s most valuable fishing resources, with the Penaeidae family having the greatest economic importance. In the southwest Atlantic the white shrimp Litopenaeus schmitti plays an important socioeconomic role for small-scale fisheries, and juveniles are targeted as live bait for recreational fisheries. This study was carried out monthly along two periods (May/2009‑January/2010 and March/2011-March/2015) at Santos estuary and aimed to investigate the relationship between morphometric and sex of the early development stages of Litopenaeus schmitti. A total of 6,978 individuals were caught and measured, with no differences (p>0.1) between sexes shown regarding total length or weight. Differences between males and females were found for Total length (TL) x Carapace length (CL) and TL x Total weight (TW) and negative allometries (b<3) were found for all relationships. The results indicate that morphometric differences among sexes seem to be more associated with total length, suggesting that TL could be a more appropriate body measurement to compare specimens of L. schmitti, at least when the analysis includes juveniles. The presence of L. schmitti specimens all year long inside the estuary reinforces the idea of a continuous reproductive cycle with peak periods. Both information comes to fulfill part of the lack of knowledge regarding this species estuarine phases.