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• H. tubulosa 43°N 1 Annual Jul–Sep Despalatović et al., 2004 42°N 2 Jul Valls, 2004 40°N 3 Aug Annual Aug–Sep Bulteel et al., 1992
• H. forskali 47°N 1, 2 Feb–Mar Annual Apr–Jun Tuwo and Conand, 1992 43°N 1 Jun–Aug & Dec Despalatović et al., 2003
• H. sanctori 28°N 2, 5 Jun–Jul Annual Jun–Aug Navarro et al., 2012
• Aslia lefevrei 53°N 1, 2 Nov–Mar Annual Mar–May Costelloe, 1988 43°N 2, 4 Oct–Jan Annual Jan–Mar Costelloe, 1988
• Parastichopus parvimensis 37°N 3 May–Jun McEuen, 1988 27°N 1, 2 Feb–Apr Annual Jan–Jul Fajardo-León et al., 2008 temperature, have well-defined similarities in their seasonal patterns. Considering that these parameters may have a significant role in the initiation of spawning (Smiley et al., 1991; Mercier and Hamel, 2009), the congruent patterns in the release timing of the gametes in H. tubulosa could be attributed to the similar profiles of temperature in the study regions (Bosc et al., 2004). Furthermore, the results from the studies analyzing the microscopic characteristics of the gonads (Despalatović et al., 2004; present study) are in agreement with findings based on different methods carried out in the Mediterranean Sea/ eastern Atlantic Ocean over different years (Table 2). The obvious convergence around the temporal allocation of spawning over summer months is an indication that high seawater temperatures (22–27 °C) may have an influence on the initiation of spawning in H. tubulosa individuals within the boundaries of the Greek Exclusive Economic Zone.
• Findings on the reproduction of the AtlantoMediterranean Holothuria forskali seem to constitute an intriguing exception to expectations around similar intraspecific characteristics within a narrow latitudinal range (Conand et al., 2002; Shiell and Uthicke, 2006; Mercier and Hamel, 2009). In the Glenan Archipelago (Brittany, ca. 47°N), the species followed an annual cycle with spawning being allocated in early spring when sea temperature was increasing (Tuwo and Conand, 1992), while in the Adriatic
• Sea, mature and spawning individuals were found during summer and winter months (Despalatović et al., 2003)
• The reasons for this divergence are unclear and further investigation is required to determine the extent of this phenomenon and underlying mechanisms. The temporal allocation of spawning recorded in H. tubulosa follows findings from several tropical Holothuria species releasing their gametes during the warm period of the year (Table 3). Reproductive patterns of tropical Table Characteristics of reproduction in tropical Holothuria species. Methods used: 1: histological examination; 2: GI; 3: spawninginduction trials. Species Latitude Location Method GI max Reproductive pattern Spawning period References H. arenacava 04°S Kenya 2 Mar Annual Mar–May Muthiga, 2006 H. atra 21°N Taiwan 1 Annual Jun–Sep Chao et al., 1994 08°N Sri Lanka 1, 2 Sep & Mar Biannual Oct & Apr
• Dissanayake and Stefansson, 2010 11°N–9°S Various 1 Continuous All year Pearse, 1968 23°S Great Barrier Reef 1, 2 May & Dec Biannual Jun & Jan Harriott, 1982 H. cinerascens 21°N Taiwan 1, 2 Jun Annual Apr–Jun Chao et al., 1995 H. difficilis 21°N Taiwan 1, 2 Aug Annual Sep Chao et al., 1995 H. fuscogilva 01°N Maldives 1, 3 Continuous Dec–Mar Reichenbach, 1999 09°S Solomon Islands 1, 2, 3 Aug–Oct Annual Aug–Oct Ramofafia et al., 2000 22°S New Caledonia 2 Nov–Dec Annual Nov–Jan Conand, 1993 H. fuscopunctata 22°S New Caledonia 2 Nov–Dec Annual Dec–Feb Conand, 1993 H. impatiens 23°S Great Barrier Reef 1, 2 Dec Annual Jan–Feb Harriott, 1985 H. leucospilota 21°N Taiwan 1, 2 Jun–Jul Annual Jun–Sep Chao et al., 1995 12°N Vietnam 1, 2 Mar & Jul Biannual Feb–Mar & Jun–Aug Nguyen and Britaev, 1992 12°S Darwin 1 Annual Late Apr
• Purwati and Luong-van, 2003 21°S Réunion 1, 2 Jan & Apr Annual Feb & May Gaudron et al., 2008 H. lubrica 24°N Bahía de La Paz 1, 2 Aug Annual Jul–Aug
• Skarbnik López et al., 2010 H. mexicana 09°N Panama 1, 2 Jul Continuous Jan, Aug, Sep Guzmán et al., 2003 H. nobilis 22°S New Caledonia 2 Jun–Jul Annual Jun–Aug Conand, 1993 H. scabra 13°N Philippines 1, 2 Continuous Jan, Jul Ong Che and Gomez, 1985 05°S Indonesia 1, 2 Apr & Oct Biannual May–Jun & Dec–Jan Tuwo, 1999 9°S Solomon Islands 1, 2 Aug & Oct Continuous Sep–Dec Ramofafia et al., 2003 22°S New Caledonia 2 Aug–Dec Biannual Aug–Sep & Dec–Jan Conand, 1993 27°S Australia 1, 2 Nov Annual Nov–Dec Morgan, 2000 H. scabra versicolor 22°S New Caledonia 2 Oct Annual Nov–Feb Conand, 1993 H. spinifera 8°N India 1, 2 Sep–Oct Annual Nov–Mar Asha and Muthiah, 2008 H. whitmaei 23°S Australia 1, 2 Apr–Jun Annual Jun–Oct Shiell and Uthicke, 2006 representatives have shown intraspecific variability between different latitudes, especially in number, timing, and duration of spawning event(s), but this variability does not seem to follow a consistent geographic pattern (i.e. longer spawning periods in regions closer to the equator compared to regions of higher latitude), with the only possible exception being the species H. atra Jaeger, 1833. Information on the life-history parameters is a prerequisite for management measures on holothurian fisheries (Guzmán et al., 2003; Muthiga et al., 2009;
• Purcell et al., 2013). Unfortunately, relevant data on H. tubulosa biology are absent (e.g., recruitment, growth, mortality, longevity) or rather limited (e.g., population density, biometrics, and reproduction) (Bulteel et al., 1992; Despalatović et al., 2004; Kazanidis et al., 2010).
• This situation constitutes a fundamental barrier for the establishment of an efficient management strategy for the natural resources of this ecosystem-engineering species. The present study provides important information on the reproduction of H. tubulosa in the eastern Mediterranean and especially in the Greek regions of the Aegean Sea through the use of histological examination. In this region, H. tubulosa has been under uncontrolled exploitation for more than a hundred years. Our study revealed an annual and synchronogamic pattern characterized by a short spawning period over summer months. High values of seawater temperature seem to have a role in the release of the gametes (Despalatović et al., 2004; Kazanidis et al., 2010; present study).
• Although the role of this species in ecosystem functioning could justify even its total exclusion from lists of harvested species (Amon and Herndl, 1991; Purcell et al., 2013), here we suggest the establishment of a seasonal ban from July to September, i.e. over its spawning period
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