Anat Tchetchik (p), Yoav Peled, Shiri Zemah-Shamir, Mordechai Shechter, Alvaro Israel

Shiri Zemah Shamir

Non-use values (NUV) are economic values that are not associated with either direct or indirect use of ecosystems. NUVs are composed of existence value (value people gain from knowing a certain feature or asset exists), bequest value (value attributed to knowing that the asset will be attainable to future generations) and altruistic value (value originating from the knowledge that other may use the asset). In order to derive NUVs for the Israeli Mediterranean the study employed a choice experiment. This valuation approach aims to elicit peoples’ utility of different features of an asset (habitats within the Israeli Mediterranean). By presenting respondents choices between different ‘bundles’ of features with different levels associated with different price levels, the willingness to pay for the features’ different levels can be obtained. The study implemented the choice experiment method and obtained a range of possible NUVs, depending on the inherent attributes of marine habitats. The resulting total NUV of the Israeli Mediterranean ranges between 223.2-594.4 million Euro per year. Compared with previous valuations of ecosystem values in the Israeli Mediterranean, the values obtained in this study are relatively high, suggesting that NUVs of the Israeli Mediterranean far outweigh other, more tangible benefits in the eyes of the Israeli general public.

Ziv Zemah Shamir (p), Shiri Zemah Shamir, Nir Becker, Aviad Scheinin, Dan Tchernov

Anat Tchetchink

In the last few winters, sharks have been aggregating near the Israeli Mediterranean coast, at a specific point, near Hadera power station. This unusual phenomenon has fascinated residents, visitors, kayakers, divers and swimmers. We analyse the effects of this intense human interest on the sharks, using contingent behaviour, in Hadera and in Ashkelon, where sharks are present but not the infrastructure for their observation. We also report on changes in shark behaviour due to change in tourism intensity. We find a change of about ILS 4.1 million annually for both sites but a larger individual consumer surplus in Hadera, where sharks are currently observable. Touristic intensity crosses the threshold level by about 12% and making the socio-equilibrium sustainable for both humans and sharks would have a social cost of ILS 0.157 million.

Ziv Zemah Shamir (p), Shiri Zemah Shamir (p), Avraham Haim, Alvaro Israel

Anat Tchetchink

Atmospheric CO2 concentration are expected to reach up to 1300 ppm, nearly three times the present concentration by the end of the current century. As an important part of global primary producers, marine macroalgae have received wide attention due to their key roles in the marine biological CO2 pump and in sustaining natural and sea-farming ecosystems. Seaweeds are also important in providing food and bioactive compounds for human benefit. In this study we examined the effects of dissolved CO2 and seawater temperature on the growth rates of two marine macroalgae, Ulva rigida (Chlorophyta) and Gracilaria conferta (Rhodophyta), common to the Israeli Mediterranean Sea shores and cultivated by the local seaweed industry. The algae were grown under continuous aeriation at ambient CO2 concentration (0.036%) or CO2-enriched seawater (0.18-0.20%), and supplied with sufficient N and P. Growth rates of the species studied were generally significantly affected on a seasonal basis by the increased CO2 concentrations in the seawater medium (190.8 average growth rate per day for U. rigida ). CK of response of photosynthetic traits in these aquatic plants is likely to be due to the presence of CO2 concentrating mechanisms (CCMs) which rely on HCO3- utilization, the inorganic carbon (Ci) form that dominates the total Ci pool available in seawater. Significant changes on the productivity of these particular marine algae species would not be anticipated when facing future increasing atmospheric CO2 levels. We modeled production functions in order to find the maximum output of growing algae under climate changes, generally, and temperature changes, particularly. In order to find the optimal temperature for maximum yields of the mariculure farmers we optimized the profits. The maximum profits obtained at 225oC for U. rigida and for G. confera around 24.5-25oC. While the maximum growth rate of U. rigida obtained at 21oC and the growth rate of the G. Confera is at 25-26 oC. This implies that the maximum growth rate is not necessarily correlated with the profits maximization due to decrease in marginal production law.

Yoav Peled, Shiri Zemah Shamir (p), Mordechai Shechter, Eyal Rahav, Alvaro Israel

Anat Tchetchink

As the scope of the ecosystem services approach expands, research on marine ecosystem services remains limited, mainly due to the lack of sufficient data and poor understanding of the processes that underlie such ecosystems. This study presents a spatiotemporal economic valuation of the climate regulation ecosystem service in the Mediterranean, which accounts for permanent and temporary carbon sequestration. Based on different carbon prices, the estimated value of climate regulation within the Israeli EEZ ranges between 265.1 and 1270.9 € km-2 year-1, which is ~2.5 to 12 fold higher than estimates by (Melaku Canu et al., 2015), for this area. Comparison with other valuations of climate regulation, which equated oceanic primary productivity (an ecosystem function) with climate regulation (an ecosystem service), points to a recurring economic overestimation of this ecosystem service