Reproductive strategy of a small endemic cyprinid, the Yarqon bleak (Acanthobrama telavivensis), in a mediterranean-type stream

Abstract

A mediterranean-type climate exists in five widely separated regions; the Mediterranean basin, parts of western North America, parts of western and southern Australia, southwestern South Africa and parts of central Chile. Streams in these regions feature seasonal disturbances of contrasting hydrology with high predictability of the timing of flooding and drying but low constancy. We would expect fish living in these streams to avoid scouring flow and breed after cessation of the flood period. The aim of the present study was to examine the adaptation of the Yarqon bleak, Acanthobrama telavivensis, an endemic cyprinid in the coastal streams of Israel, to mediterranean-type stream 1 conditions. For that we studied its reproductive strategy (age at maturity and life span, gonad activity, oocyte maturation, spawning activity and habitats, appearance of juveniles), in a major costal stream (Yarqon). Our findings show that the Yarqon bleak exhibits life history traits attuned with a mediterranean-climate hydrologic regime. It breeds in late winter and early spring, a window of opportunity between flash floods and habitat desiccation. Being a multiple spawner allows the fish to compensate for the potential loss of part of its reproductive output due to scouring flows of late floods. The ability of the Yarqon bleak to spawn on different substrate-types enables it to take advantage of different stream conditions that pertain in different years. The fish attains preadult size (ca. 33-42 mm) within the first year, prior to drying out of most stream reaches, and matures by the beginning of the second year (males >41; females >42 mm). The cost of these tactics is a short life span (4-5 age groups). The reproductive strategy of the Yarqon bleak falls into the category of in-channel breeding but, unlike the case suggested by a low flow recruitment model, the fish breed during the period of flood cessation, a transitional time between high and low flows, rather than at the time of low flow. Breeding at this time of the year in mediterranean-type streams puts early stages somewhat at risk of being washed away by late floods, but gains them a longer period of growth under favorable conditions. We suggest an additional positive tradeoff that should be investigated: the reduced competition with age 0 of other fish that breed later in the season. This suggested model of recruitment during the period of flood cessation seems appropriate for fish in streams with 1 mediterranean-written with a small m, is used in connection with climate or ecological region and is distinguished from Mediterranean that is used in a geographical context, referring to the Mediterranean basin.

Variability in feeding ecology of a South American cichlid: a reason for successful invasion in mediterranean‐type rivers?

“…No exact reason is known for this introduction, although A. facetus is commonly used as an ornamental species (Lever 1996;Ř íčan & Kullander 2006). Presently, the species is established in several mediterranean-type (sensu Elron et al 2006) (Collares-Pereira et al 2000). Nevertheless, factors contributing to the invasiveness of A. facetus in mediterranean-type rivers remain unclear, and knowledge of its biological attributes is limited both outside and within the native range.…”

Fine-Scale Temporal Dynamics of a Fragmented Lotic Microbial Ecosystem

“…The Yarqon stream, which runs through the center of Israel's coastal plain 15 , into the Mediterranean Sea, consists mostly (about 70%) of treated wastewater of variable quality 16 17 and a fixed 400 cubic meters per hour influx of fresh water, pumped from the “Yarqon-Taninim” aquifer . The Seven Mills (“Sheva Tahanot”) weir ( Fig 1 .)…”

Rediscovery of Acanthobrama hadiyahensis (Cyprinidae) in Saudi Arabia

“…According to Coad et al (), the species most closely related to A. hadiyahensis is Acanthobrama telavivensis Goren, Fishelson & Trewavas 1973. This latter species was found to be a multiple spawner that breeds in late winter and early spring (Elron et al , ).…”